+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you. +
+``` + +``` ++ You complete my darkness with your light. I love: +
-
+
- the way you see good in the worse +
- the way you handle emotionally difficult situations +
- the way you look at Justice +
`，因为每个 `
- ` 和 `
` 元素那样定义 `
- ` 元素的宽度。这是因为 `
- the way you see good in the worse +
- the way you handle emotionally difficult situations +
- the way you look at Justice +
- the way you see good in the worse +
- the way you handle emotionally difficult situations +
- the way you look at Justice +
- the way you see good in the worse +
- the way you handle emotionally difficult situations +
- the way you look at Justice +
- the way you see good in the worse +
- the way you handle emotionally difficult situations +
- the way you look at Justice +
- the way you see good in the worse +
- the way you handle emotionally difficult situations +
- the way you look at Justice +
- the way you see good in the worse +
- the way you handle emotionally difficult situations +
- the way you look at Justice +
- the way you see good in the worse +
- the way you handle emotionally difficult situations +
- the way you look at Justice +
- the way you see good in the worse +
- the way you handle emotionally difficult situations +
- the way you look at Justice +
- the way you see good in the worse +
- the way you handle emotionally difficult situations +
- the way you look at Justice +
- the way you see good in the worse +
- the way you handle emotionally difficult situations +
- the way you look at Justice +
- the way you see good in the worse +
- the way you handle emotionally difficult situations +
- the way you look at Justice +
- the way you see good in the worse +
- the way you handle emotionally difficult situations +
- the way you look at Justice +
- `：显示列表
+ * ``：用于分组我们信件的元素 + * `
`、`
`：用于标题和子标题 + * `
`：用于插入图像 + * ``、``：用于粗体和斜体文字样式 + * `. - -* Linked stylesheet: We write styles of all the elements in a separate file with .css extension. This file is called Stylesheet. - -Let’s have a look at how we defined the inline style of the “div” until now: - -``` -
-``` - -We can write this same style inside `` like this: - -``` -div{ - width:550px; -} -``` - -In embedded styling, the styles we write are separate from the elements. So we need a way to relate the element and its style. The first word “div” does exactly that. It lets the browser know that whatever style is inside the curly braces `{…}` belongs to the “div” element. Since this phrase determines which element to apply the style to, it’s called a selector. - -The way we write style remains same: property(width) and value(550px) separated by a colon(:) and ended by a semicolon(;). - -Let’s remove inline style from our “div” and “img” element and write it inside the ` -``` - -``` ---``` - -Save and refresh, and the result should remain the same. - -There is one big problem though — what if there is more than one “div” and “img” element in our HTML file? The styles that we defined for div and img inside the “style” element will apply to every div and img on the page. - -If you add another div in your code in the future, then that div will also become 550px wide. We don’t want that. - -We want to apply our styles to the specific div and img that we are using right now. To do this, we need to give our div and img element unique ids. Here’s how you can give an id to an element using its “id” attribute: - -``` -Bat Letter
-
- - After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you. -
-``` - -``` -You are the light of my life
-- You complete my darkness with your light. I love: -
--
-
- the way you see good in the worse -
- the way you handle emotionally difficult situations -
- the way you look at Justice -
- I have learned a lot from you. You have occupied a special place in my heart over the time. -
-I have a confession to make
-- It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart. -
-- I don't show my emotions, but I think this man behind the mask is falling for you. -
-I love you Superman.
-- Your not-so-secret-lover,
-
- Batman --``` - -and here’s how to use th diff --git a/sources/tech/20180226 -Getting to Done- on the Linux command line.md b/sources/tech/20180226 -Getting to Done- on the Linux command line.md index c325a0d884..321a3e3002 100644 --- a/sources/tech/20180226 -Getting to Done- on the Linux command line.md +++ b/sources/tech/20180226 -Getting to Done- on the Linux command line.md @@ -1,3 +1,5 @@ +Translating by Guevaraya + 'Getting to Done' on the Linux command line ====== diff --git a/sources/tech/20180326 Manage your workstation with Ansible- Automating configuration.md b/sources/tech/20180326 Manage your workstation with Ansible- Automating configuration.md index 21821a070c..b504b48ae0 100644 --- a/sources/tech/20180326 Manage your workstation with Ansible- Automating configuration.md +++ b/sources/tech/20180326 Manage your workstation with Ansible- Automating configuration.md @@ -1,4 +1,4 @@ -Manage your workstation with Ansible: Automating configuration +Manage your workstation with Ansible: Automating configuration Translating By FelixYFZ ======  diff --git a/sources/tech/20180402 An introduction to the Flask Python web app framework.md b/sources/tech/20180402 An introduction to the Flask Python web app framework.md new file mode 100644 index 0000000000..4b07338bc5 --- /dev/null +++ b/sources/tech/20180402 An introduction to the Flask Python web app framework.md @@ -0,0 +1,451 @@ +[#]: collector: (lujun9972) +[#]: translator: ( ) +[#]: reviewer: ( ) +[#]: publisher: ( ) +[#]: subject: (An introduction to the Flask Python web app framework) +[#]: via: (https://opensource.com/article/18/4/flask) +[#]: author: (Nicholas Hunt-Walker https://opensource.com/users/nhuntwalker) +[#]: url: ( ) + +An introduction to the Flask Python web app framework +====== +In the first part in a series comparing Python frameworks, learn about Flask. + + +If you're developing a web app in Python, chances are you're leveraging a framework. A [framework][1] "is a code library that makes a developer's life easier when building reliable, scalable, and maintainable web applications" by providing reusable code or extensions for common operations. There are a number of frameworks for Python, including [Flask][2], [Tornado][3], [Pyramid][4], and [Django][5]. New Python developers often ask: Which framework should I use? + + * New visitors to the site should be able to register new accounts. + * Registered users can log in, log out, see information for their profiles, and edit their information. + * Registered users can create new task items, see their existing tasks, and edit existing tasks. + + + +This series is designed to help developers answer that question by comparing those four frameworks. To compare their features and operations, I'll take each one through the process of constructing an API for a simple To-Do List web application. The API is itself fairly straightforward: + +All this rounds out to a compact set of API endpoints that each backend must implement, along with the allowed HTTP methods: + + * `GET /` + * `POST /accounts` + * `POST /accounts/login` + * `GET /accounts/logout` + * `GET, PUT, DELETE /accounts/` + * `GET, POST /accounts/ /tasks` + * `GET, PUT, DELETE /accounts/ /tasks/ ` + + + +Each framework has a different way to put together its routes, models, views, database interaction, and overall application configuration. I'll describe those aspects of each framework in this series, which will begin with Flask. + +### Flask startup and configuration + +Like most widely used Python libraries, the Flask package is installable from the [Python Package Index][6] (PPI). First create a directory to work in (something like `flask_todo` is a fine directory name) then install the `flask` package. You'll also want to install `flask-sqlalchemy` so your Flask application has a simple way to talk to a SQL database. + +I like to do this type of work within a Python 3 virtual environment. To get there, enter the following on the command line: + +``` +$ mkdir flask_todo +$ cd flask_todo +$ pipenv install --python 3.6 +$ pipenv shell +(flask-someHash) $ pipenv install flask flask-sqlalchemy +``` + +If you want to turn this into a Git repository, this is a good place to run `git init`. It'll be the root of the project, and if you want to export the codebase to a different machine, it will help to have all the necessary setup files here. + +A good way to get moving is to turn the codebase into an installable Python distribution. At the project's root, create `setup.py` and a directory called `todo` to hold the source code. + +The `setup.py` should look something like this: + +``` +from setuptools import setup, find_packages + +requires = [ + 'flask', + 'flask-sqlalchemy', + 'psycopg2', +] + +setup( + name='flask_todo', + version='0.0', + description='A To-Do List built with Flask', + author=' ', + author_email=' ', + keywords='web flask', + packages=find_packages(), + include_package_data=True, + install_requires=requires +) +``` + +This way, whenever you want to install or deploy your project, you'll have all the necessary packages in the `requires` list. You'll also have everything you need to set up and install the package in `site-packages`. For more information on how to write an installable Python distribution, check out [the docs on setup.py][7]. + +Within the `todo` directory containing your source code, create an `app.py` file and a blank `__init__.py` file. The `__init__.py` file allows you to import from `todo` as if it were an installed package. The `app.py` file will be the application's root. This is where all the `Flask` application goodness will go, and you'll create an environment variable that points to that file. If you're using `pipenv` (like I am), you can locate your virtual environment with `pipenv --venv` and set up that environment variable in your environment's `activate` script. + +``` +# in your activate script, probably at the bottom (but anywhere will do) + +export FLASK_APP=$VIRTUAL_ENV/../todo/app.py +export DEBUG='True' +``` + +When you installed `Flask`, you also installed the `flask` command-line script. Typing `flask run` will prompt the virtual environment's Flask package to run an HTTP server using the `app` object in whatever script the `FLASK_APP` environment variable points to. The script above also includes an environment variable named `DEBUG` that will be used a bit later. + +Let's talk about this `app` object. + +In `todo/app.py`, you'll create an `app` object, which is an instance of the `Flask` object. It'll act as the central configuration object for the entire application. It's used to set up pieces of the application required for extended functionality, e.g., a database connection and help with authentication. + +It's regularly used to set up the routes that will become the application's points of interaction. To explain what this means, let's look at the code it corresponds to. + +``` +from flask import Flask + +app = Flask(__name__) + +@app.route('/') +def hello_world(): + """Print 'Hello, world!' as the response body.""" + return 'Hello, world!' +``` + +This is the most basic complete Flask application. `app` is an instance of `Flask`, taking in the `__name__` of the script file. This lets Python know how to import from files relative to this one. The `app.route` decorator decorates the first **view** function; it can specify one of the routes used to access the application. (We'll look at this later.) + +Any view you specify must be decorated by `app.route` to be a functional part of the application. You can have as many functions as you want scattered across the application, but in order for that functionality to be accessible from anything external to the application, you must decorate that function and specify a route to make it into a view. + +In the example above, when the app is running and accessed at `http://domainname/`, a user will receive `"Hello, World!"` as a response. + +### Connecting the database in Flask + +While the code example above represents a complete Flask application, it doesn't do anything interesting. One interesting thing a web application can do is persist user data, but it needs the help of and connection to a database. + +Flask is very much a "do it yourself" web framework. This means there's no built-in database interaction, but the `flask-sqlalchemy` package will connect a SQL database to a Flask application. The `flask-sqlalchemy` package needs just one thing to connect to a SQL database: The database URL. + +Note that a wide variety of SQL database management systems can be used with `flask-sqlalchemy`, as long as the DBMS has an intermediary that follows the [DBAPI-2 standard][8]. In this example, I'll use PostgreSQL (mainly because I've used it a lot), so the intermediary to talk to the Postgres database is the `psycopg2` package. Make sure `psycopg2` is installed in your environment and include it in the list of required packages in `setup.py`. You don't have to do anything else with it; `flask-sqlalchemy` will recognize Postgres from the database URL. + +Flask needs the database URL to be part of its central configuration through the `SQLALCHEMY_DATABASE_URI` attribute. A quick and dirty solution is to hardcode a database URL into the application. + +``` +# top of app.py +from flask import Flask +from flask_sqlalchemy import SQLAlchemy + +app = Flask(__name__) +app.config['SQLALCHEMY_DATABASE_URI'] = 'postgres://localhost:5432/flask_todo' +db = SQLAlchemy(app) +``` + +However, this is not a sustainable solution. If you change databases or don't want your database URL visible in source control, you'll have to take extra steps to ensure your information is appropriate for the environment. + +You can make things simpler by using environment variables. They will ensure that, no matter what machine the code runs on, it always points at the right stuff if that stuff is configured in the running environment. It also ensures that, even though you need that information to run the application, it never shows up as a hardcoded value in source control. + +In the same place you declared `FLASK_APP`, declare a `DATABASE_URL` pointing to the location of your Postgres database. Development tends to work locally, so just point to your local database. + +``` +# also in your activate script + +export DATABASE_URL='postgres://localhost:5432/flask_todo' +``` + +Now in `app.py`, include the database URL in your app configuration. + +``` +app.config['SQLALCHEMY_DATABASE_URI'] = os.environ.get('DATABASE_URL', '') +db = SQLAlchemy(app) +``` + +And just like that, your application has a database connection! + +### Defining objects in Flask + +Having a database to talk to is a good first step. Now it's time to define some objects to fill that database. + +In application development, a "model" refers to the data representation of some real or conceptual object. For example, if you're building an application for a car dealership, you may define a `Car` model that encapsulates all of a car's attributes and behavior. + +In this case, you're building a To-Do List with Tasks, and each Task belongs to a User. Before you think too deeply about how they're related to each other, start by defining objects for Tasks and Users. + +The `flask-sqlalchemy` package leverages [SQLAlchemy][9] to set up and inform the database structure. You'll define a model that will live in the database by inheriting from the `db.Model` object and define the attributes of those models as `db.Column` instances. For each column, you must specify a data type, so you'll pass that data type into the call to `db.Column` as the first argument. + +Because the model definition occupies a different conceptual space than the application configuration, make `models.py` to hold model definitions separate from `app.py`. The Task model should be constructed to have the following attributes: + + * `id`: a value that's a unique identifier to pull from the database + * `name`: the name or title of the task that the user will see when the task is listed + * `note`: any extra comments that a person might want to leave with their task + * `creation_date`: the date and time the task was created + * `due_date`: the date and time the task is due to be completed (if at all) + * `completed`: a way to indicate whether or not the task has been completed + + + +Given this attribute list for Task objects, the application's `Task` object can be defined like so: + +``` +from .app import db +from datetime import datetime + +class Task(db.Model): + """Tasks for the To Do list.""" + id = db.Column(db.Integer, primary_key=True) + name = db.Column(db.Unicode, nullable=False) + note = db.Column(db.Unicode) + creation_date = db.Column(db.DateTime, nullable=False) + due_date = db.Column(db.DateTime) + completed = db.Column(db.Boolean, default=False) + + def __init__(self, *args, **kwargs): + """On construction, set date of creation.""" + super().__init__(*args, **kwargs) + self.creation_date = datetime.now() +``` + +Note the extension of the class constructor method. At the end of the day, any model you construct is still a Python object and therefore must go through construction in order to be instantiated. It's important to ensure that the creation date of the model instance reflects its actual date of creation. You can explicitly set that relationship by effectively saying, "when an instance of this model is constructed, record the date and time and set it as the creation date." + +### Model relationships + +In a given web application, you may want to be able to express relationships between objects. In the To-Do List example, users own multiple tasks, and each task is owned by only one user. This is an example of a "many-to-one" relationship, also known as a foreign key relationship, where the tasks are the "many" and the user owning those tasks is the "one." + +In Flask, a many-to-one relationship can be specified using the `db.relationship` function. First, build the User object. + +``` +class User(db.Model): + """The User object that owns tasks.""" + id = db.Column(db.Integer, primary_key=True) + username = db.Column(db.Unicode, nullable=False) + email = db.Column(db.Unicode, nullable=False) + password = db.Column(db.Unicode, nullable=False) + date_joined = db.Column(db.DateTime, nullable=False) + token = db.Column(db.Unicode, nullable=False) + + def __init__(self, *args, **kwargs): + """On construction, set date of creation.""" + super().__init__(*args, **kwargs) + self.date_joined = datetime.now() + self.token = secrets.token_urlsafe(64) +``` + +It looks very similar to the Task object; you'll find that most objects have the same basic format of class attributes as table columns. Every once in a while, you'll run into something a little different, including some multiple-inheritance magic, but this is the norm. + +Now that the `User` model is created, you can set up the foreign key relationship. For the "many," set fields for the `user_id` of the `User` that owns this task, as well as the `user` object with that ID. Also make sure to include a keyword argument (`back_populates`) that updates the User model when the task gets a user as an owner. + +For the "one," set a field for the `tasks` the specific user owns. Similar to maintaining the two-way relationship on the Task object, set a keyword argument on the User's relationship field to update the Task when it is assigned to a user. + +``` +# on the Task object +user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False) +user = db.relationship("user", back_populates="tasks") + +# on the User object +tasks = db.relationship("Task", back_populates="user") +``` + +### Initializing the database + +Now that the models and model relationships are set, start setting up your database. Flask doesn't come with its own database-management utility, so you'll have to write your own (to some degree). You don't have to get fancy with it; you just need something to recognize what tables are to be created and some code to create them (or drop them should the need arise). If you need something more complex, like handling updates to database tables (i.e., database migrations), you'll want to look into a tool like [Flask-Migrate][10] or [Flask-Alembic][11]. + +Create a script called `initializedb.py` next to `setup.py` for managing the database. (Of course, it doesn't need to be called this, but why not give names that are appropriate to a file's function?) Within `initializedb.py`, import the `db` object from `app.py` and use it to create or drop tables. `initializedb.py` should end up looking something like this: + +``` +from todo.app import db +import os + +if bool(os.environ.get('DEBUG', '')): + db.drop_all() +db.create_all() +``` + +If a `DEBUG` environment variable is set, drop tables and rebuild. Otherwise, just create the tables once and you're good to go. + +### Views and URL config + +The last bits needed to connect the entire application are the views and routes. In web development, a "view" (in concept) is functionality that runs when a specific access point (a "route") in your application is hit. These access points appear as URLs: paths to functionality in an application that return some data or handle some data that has been provided. The views will be logical structures that handle specific HTTP requests from a given client and return some HTTP response to that client. + +In Flask, views appear as functions; for example, see the `hello_world` view above. For simplicity, here it is again: + +``` +@app.route('/') +def hello_world(): + """Print 'Hello, world!' as the response body.""" + return 'Hello, world!' +``` + +When the route of `http://domainname/` is accessed, the client receives the response, "Hello, world!" + +With Flask, a function is marked as a view when it is decorated by `app.route`. In turn, `app.route` adds to the application's central configuration a map from the specified route to the function that runs when that route is accessed. You can use this to start building out the rest of the API. + +Start with a view that handles only `GET` requests, and respond with the JSON representing all the routes that will be accessible and the methods that can be used to access them. + +``` +from flask import jsonify + +@app.route('/api/v1', methods=["GET"]) +def info_view(): + """List of routes for this API.""" + output = { + 'info': 'GET /api/v1', + 'register': 'POST /api/v1/accounts', + 'single profile detail': 'GET /api/v1/accounts/ ', + 'edit profile': 'PUT /api/v1/accounts/ ', + 'delete profile': 'DELETE /api/v1/accounts/ ', + 'login': 'POST /api/v1/accounts/login', + 'logout': 'GET /api/v1/accounts/logout', + "user's tasks": 'GET /api/v1/accounts/ /tasks', + "create task": 'POST /api/v1/accounts/ /tasks', + "task detail": 'GET /api/v1/accounts/ /tasks/ ', + "task update": 'PUT /api/v1/accounts/ /tasks/ ', + "delete task": 'DELETE /api/v1/accounts/ /tasks/ ' + } + return jsonify(output) +``` + +Since you want your view to handle one specific type of HTTP request, use `app.route` to add that restriction. The `methods` keyword argument will take a list of strings as a value, with each string a type of possible HTTP method. In practice, you can use `app.route` to restrict to one or more types of HTTP request or accept any by leaving the `methods` keyword argument alone. + +Whatever you intend to return from your view function **must** be a string or an object that Flask turns into a string when constructing a properly formatted HTTP response. The exceptions to this rule are when you're trying to handle redirects and exceptions thrown by your application. What this means for you, the developer, is that you need to be able to encapsulate whatever response you're trying to send back to the client into something that can be interpreted as a string. + +A good structure that contains complexity but can still be stringified is a Python dictionary. Therefore, I recommend that, whenever you want to send some data to the client, you choose a Python `dict` with whatever key-value pairs you need to convey information. To turn that dictionary into a properly formatted JSON response, headers and all, pass it as an argument to Flask's `jsonify` function (`from flask import jsonify`). + +The view function above takes what is effectively a listing of every route that this API intends to handle and sends it to the client whenever the `http://domainname/api/v1` route is accessed. Note that, on its own, Flask supports routing to exactly matching URIs, so accessing that same route with a trailing `/` would create a 404 error. If you wanted to handle both with the same view function, you'd need stack decorators like so: + +``` +@app.route('/api/v1', methods=["GET"]) +@app.route('/api/v1/', methods=["GET"]) +def info_view(): + # blah blah blah more code +``` + +An interesting case is that if the defined route had a trailing slash and the client asked for the route without the slash, you wouldn't need to double up on decorators. Flask would redirect the client's request appropriately. It's odd that it doesn't work both ways. + +### Flask requests and the DB + +At its base, a web framework's job is to handle incoming HTTP requests and return HTTP responses. The previously written view doesn't really have much to do with HTTP requests aside from the URI that was accessed. It doesn't process any data. Let's look at how Flask behaves when data needs handling. + +The first thing to know is that Flask doesn't provide a separate `request` object to each view function. It has **one** global request object that every view function can use, and that object is conveniently named `request` and is importable from the Flask package. + +The next thing is that Flask's route patterns can have a bit more nuance. One scenario is a hardcoded route that must be matched perfectly to activate a view function. Another scenario is a route pattern that can handle a range of routes, all mapping to one view by allowing a part of that route to be variable. If the route in question has a variable, the corresponding value can be accessed from the same-named variable in the view's parameter list. + +``` +@app.route('/a/sample/ /route) +def some_view(variable): + # some code blah blah blah +``` + +To communicate with the database within a view, you must use the `db` object that was populated toward the top of the script. Its `session` attribute is your connection to the database when you want to make changes. If you just want to query for objects, the objects built from `db.Model` have their own database interaction layer through the `query` attribute. + +Finally, any response you want from a view that's more complex than a string must be built deliberately. Previously you built a response using a "jsonified" dictionary, but certain assumptions were made (e.g., 200 status code, status message "OK," Content-Type of "text/plain"). Any special sauce you want in your HTTP response must be added deliberately. + +Knowing these facts about working with Flask views allows you to construct a view whose job is to create new `Task` objects. Let's look at the code (below) and address it piece by piece. + +``` +from datetime import datetime +from flask import request, Response +from flask_sqlalchemy import SQLAlchemy +import json + +from .models import Task, User + +app = Flask(__name__) +app.config['SQLALCHEMY_DATABASE_URI'] = os.environ.get('DATABASE_URL', '') +db = SQLAlchemy(app) + +INCOMING_DATE_FMT = '%d/%m/%Y %H:%M:%S' + +@app.route('/api/v1/accounts/ /tasks', methods=['POST']) +def create_task(username): + """Create a task for one user.""" + user = User.query.filter_by(username=username).first() + if user: + task = Task( + name=request.form['name'], + note=request.form['note'], + creation_date=datetime.now(), + due_date=datetime.strptime(due_date, INCOMING_DATE_FMT) if due_date else None, + completed=bool(request.form['completed']), + user_id=user.id, + ) + db.session.add(task) + db.session.commit() + output = {'msg': 'posted'} + response = Response( + mimetype="application/json", + response=json.dumps(output), + status=201 + ) + return response +``` + +Let's start with the `@app.route` decorator. The route is `'/api/v1/accounts/ /tasks'`, where ` ` is a route variable. Put angle brackets around any part of the route you want to be variable, then include that part of the route on the next line in the parameter list **with the same name**. The only parameters that should be in the parameter list should be the variables in your route. + +Next comes the query: + +``` +user = User.query.filter_by(username=username).first() +``` + +To look for one user by username, conceptually you need to look at all the User objects stored in the database and find the users with the username matching the one that was requested. With Flask, you can ask the `User` object directly through the `query` attribute for the instance matching your criteria. This type of query would provide a list of objects (even if it's only one object or none at all), so to get the object you want, just call `first()`. + +``` +task = Task( + name=request.form['name'], + note=request.form['note'], + creation_date=datetime.now(), + due_date=datetime.strptime(due_date, INCOMING_DATE_FMT) if due_date else None, + completed=bool(request.form['completed']), + user_id=user.id, +) +``` + +Whenever data is sent to the application, regardless of the HTTP method used, that data is stored on the `form` attribute of the `request` object. The name of the field on the frontend will be the name of the key mapped to that data in the `form` dictionary. It'll always come in the form of a string, so if you want your data to be a specific data type, you'll have to make it explicit by casting it as the appropriate type. + +The other thing to note is the assignment of the current user's user ID to the newly instantiated `Task`. This is how that foreign key relationship is maintained. + +``` +db.session.add(task) +db.session.commit() +``` + +Creating a new `Task` instance is great, but its construction has no inherent connection to tables in the database. In order to insert a new row into the corresponding SQL table, you must use the `session` attached to the `db` object. The `db.session.add(task)` stages the new `Task` instance to be added to the table, but doesn't add it yet. While it's done only once here, you can add as many things as you want before committing. The `db.session.commit()` takes all the staged changes, or "commits," and applies them to the corresponding tables in the database. + +``` +output = {'msg': 'posted'} +response = Response( + mimetype="application/json", + response=json.dumps(output), + status=201 +) +``` + +The response is an actual instance of a `Response` object with its `mimetype`, body, and `status` set deliberately. The goal for this view is to alert the user they created something new. Seeing how this view is supposed to be part of a backend API that sends and receives JSON, the response body must be JSON serializable. A dictionary with a simple string message should suffice. Ensure that it's ready for transmission by calling `json.dumps` on your dictionary, which will turn your Python object into valid JSON. This is used instead of `jsonify`, as `jsonify` constructs an actual response object using its input as the response body. In contrast, `json.dumps` just takes a given Python object and converts it into a valid JSON string if possible. + +By default, the status code of any response sent with Flask will be `200`. That will work for most circumstances, where you're not trying to send back a specific redirection-level or error-level message. Since this case explicitly lets the frontend know when a new item has been created, set the status code to be `201`, which corresponds to creating a new thing. + +And that's it! That's a basic view for creating a new `Task` object in Flask given the current setup of your To-Do List application. Similar views could be constructed for listing, editing, and deleting tasks, but this example offers an idea of how it could be done. + +### The bigger picture + +There is much more that goes into an application than one view for creating new things. While I haven't discussed anything about authorization/authentication systems, testing, database migration management, cross-origin resource sharing, etc., the details above should give you more than enough to start digging into building your own Flask applications. + +Learn more Python at [PyCon Cleveland 2018][12]. + +-------------------------------------------------------------------------------- + +via: https://opensource.com/article/18/4/flask + +作者：[Nicholas Hunt-Walker][a] +选题：[lujun9972][b] +译者：[译者ID](https://github.com/译者ID) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]: https://opensource.com/users/nhuntwalker +[b]: https://github.com/lujun9972 +[1]: https://www.fullstackpython.com/web-frameworks.html +[2]: http://flask.pocoo.org/ +[3]: http://www.tornadoweb.org/en/stable/ +[4]: https://trypyramid.com/ +[5]: https://www.djangoproject.com/ +[6]: https://pypi.python.org +[7]: https://docs.python.org/3/distutils/setupscript.html +[8]: https://www.python.org/dev/peps/pep-0249/ +[9]: https://www.sqlalchemy.org/ +[10]: https://flask-migrate.readthedocs.io/en/latest/ +[11]: https://flask-alembic.readthedocs.io/en/stable/ +[12]: https://us.pycon.org/2018/ diff --git a/sources/tech/20180417 How To Browse Stack Overflow From Terminal.md b/sources/tech/20180417 How To Browse Stack Overflow From Terminal.md deleted file mode 100644 index 0bd7789d87..0000000000 --- a/sources/tech/20180417 How To Browse Stack Overflow From Terminal.md +++ /dev/null @@ -1,140 +0,0 @@ -translating---geekpi - -How To Browse Stack Overflow From Terminal -====== - - -A while ago, we have written about [**SoCLI**][1], a python script to search and browse Stack Overflow website from command line. Today, we will discuss about a similar tool named **“how2”**. It is a command line utility to browse Stack Overflow from Terminal. You can query in the plain English as the way you do in [**Google search**][2] and it uses Google and Stackoverflow APIs to search for the given queries. It is free and open source utility written using NodeJS. - -### Browse Stack Overflow From Terminal Using how2 - -Since how2 is a NodeJS package, we can install it using Npm package manager. If you haven’t installed Npm and NodeJS already, refer the following guide. - -After installing Npm and NodeJS, run the following command to install how2 utility. -``` -$ npm install -g how2 - -``` - -Now let us see how to browse Stack Overflow uisng this program. The typical usage to search through Stack Overflow site using “how2” utility is: -``` -$ how2 - -``` - -For example, I am going to search for how to create tgz archive. -``` -$ how2 create archive tgz - -``` - -Oops! I get the following error. -``` -/home/sk/.nvm/versions/node/v9.11.1/lib/node_modules/how2/node_modules/devnull/transports/transport.js:59 -Transport.prototype.__proto__ = EventEmitter.prototype; - ^ - - TypeError: Cannot read property 'prototype' of undefined - at Object. (/home/sk/.nvm/versions/node/v9.11.1/lib/node_modules/how2/node_modules/devnull/transports/transport.js:59:46) - at Module._compile (internal/modules/cjs/loader.js:654:30) - at Object.Module._extensions..js (internal/modules/cjs/loader.js:665:10) - at Module.load (internal/modules/cjs/loader.js:566:32) - at tryModuleLoad (internal/modules/cjs/loader.js:506:12) - at Function.Module._load (internal/modules/cjs/loader.js:498:3) - at Module.require (internal/modules/cjs/loader.js:598:17) - at require (internal/modules/cjs/helpers.js:11:18) - at Object. (/home/sk/.nvm/versions/node/v9.11.1/lib/node_modules/how2/node_modules/devnull/transports/stream.js:8:17) - at Module._compile (internal/modules/cjs/loader.js:654:30) - -``` - -I may be a bug. I hope it gets fixed in the future versions. However, I find a workaround posted [**here**][3]. - -To fix this error temporarily, you need to edit the **transport.js** file using command: -``` -$ vi /home/sk/.nvm/versions/node/v9.11.1/lib/node_modules/how2/node_modules/devnull/transports/transport.js - -``` - -The actual path of this file will be displayed in your error output. Replace the above file path with your own. Then find the following line: -``` -var EventEmitter = process.EventEmitter; - -``` - -and replace it with following line: -``` -var EventEmitter = require('events'); - -``` - -Press ESC and type **:wq** to save and quit the file. - -Now search again the query. -``` -$ how2 create archive tgz - -``` - -Here is the sample output from my Ubuntu system. - -[![][4]][5] - -If the answer you’re looking for is not displayed in the above output, press **SPACE BAR** key to start the interactive search where you can go through all suggested questions and answers from the Stack Overflow site. - -[![][4]][6] - -Use UP/DOWN arrows to move between the results. Once you got the right answer/question, hit SPACE BAR or ENTER key to open it in the Terminal. - -[![][4]][7] - -To go back and exit, press **ESC**. - -**Search answers for specific language** - -If you don’t specify a language it **defaults to Bash** unix command line and give you immediately the most likely answer as above. You can also narrow the results to a specific language, for example perl, python, c, Java etc. - -For instance, to search for queries related to “Python” language only using **-l** flag as shown below. -``` -$ how2 -l python linked list - -``` - -[![][4]][8] - -To get a quick help, type: -``` -$ how2 -h - -``` - -### Conclusion - -The how2 utility is a basic command line program to quickly search for questions and answers from Stack Overflow without leaving your Terminal and it does this job pretty well. However, it is just CLI browser for Stack overflow. For some advanced features such as searching most voted questions, searching queries using multiple tags, colored interface, submitting a new question and viewing questions stats etc., **SoCLI** is good to go. - -And, that’s all for now. Hope this was useful. I will be soon here with another useful guide. Until then, stay tuned with OSTechNix! - -Cheers! - - - --------------------------------------------------------------------------------- - -via: https://www.ostechnix.com/how-to-browse-stack-overflow-from-terminal/ - -作者：[SK][a] -译者：[译者ID](https://github.com/译者ID) -校对：[校对者ID](https://github.com/校对者ID) -选题：[lujun9972](https://github.com/lujun9972) - -本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 - -[a]:https://www.ostechnix.com/author/sk/ -[1]:https://www.ostechnix.com/search-browse-stack-overflow-website-commandline/ -[2]:https://www.ostechnix.com/google-search-navigator-enhance-keyboard-navigation-in-google-search/ -[3]:https://github.com/santinic/how2/issues/79 -[4]:data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7 -[5]:http://www.ostechnix.com/wp-content/uploads/2018/04/stack-overflow-1.png -[6]:http://www.ostechnix.com/wp-content/uploads/2018/04/stack-overflow-2.png -[7]:http://www.ostechnix.com/wp-content/uploads/2018/04/stack-overflow-3.png -[8]:http://www.ostechnix.com/wp-content/uploads/2018/04/stack-overflow-4.png diff --git a/sources/tech/20180420 How To Remove Password From A PDF File in Linux.md b/sources/tech/20180420 How To Remove Password From A PDF File in Linux.md index 0e4318c858..09ac06d6b0 100644 --- a/sources/tech/20180420 How To Remove Password From A PDF File in Linux.md +++ b/sources/tech/20180420 How To Remove Password From A PDF File in Linux.md @@ -1,3 +1,4 @@ +robsean translating How To Remove Password From A PDF File in Linux ====== diff --git a/sources/tech/20180514 An introduction to the Pyramid web framework for Python.md b/sources/tech/20180514 An introduction to the Pyramid web framework for Python.md new file mode 100644 index 0000000000..a16e604774 --- /dev/null +++ b/sources/tech/20180514 An introduction to the Pyramid web framework for Python.md @@ -0,0 +1,617 @@ +[#]: collector: (lujun9972) +[#]: translator: ( ) +[#]: reviewer: ( ) +[#]: publisher: ( ) +[#]: subject: (An introduction to the Pyramid web framework for Python) +[#]: via: (https://opensource.com/article/18/5/pyramid-framework) +[#]: author: (Nicholas Hunt-Walker https://opensource.com/users/nhuntwalker) +[#]: url: ( ) + +An introduction to the Pyramid web framework for Python +====== +In the second part in a series comparing Python frameworks, learn about Pyramid. + + +In the [first article][1] in this four-part series comparing different Python web frameworks, I explained how to create a To-Do List web application in the [Flask][2] web framework. In this second article, I'll do the same task with the [Pyramid][3] web framework. Future articles will look at [Tornado][4] and [Django][5]; as I go along, I'll explore more of the differences among them. + +### Installing, starting up, and doing configuration + +Self-described as "the start small, finish big, stay finished framework," Pyramid is much like Flask in that it takes very little effort to get it up and running. In fact, you'll recognize many of the same patterns as you build out this application. The major difference between the two, however, is that Pyramid comes with several useful utilities, which I'll describe shortly. + +To get started, create a virtual environment and install the package. + +``` +$ mkdir pyramid_todo +$ cd pyramid_todo +$ pipenv install --python 3.6 +$ pipenv shell +(pyramid-someHash) $ pipenv install pyramid +``` + +As with Flask, it's smart to create a `setup.py` file to make the app you build an easily installable Python distribution. + +``` +# setup.py +from setuptools import setup, find_packages + +requires = [ + 'pyramid', + 'paster_pastedeploy', + 'pyramid-ipython', + 'waitress' +] + +setup( + name='pyramid_todo', + version='0.0', + description='A To-Do List build with Pyramid', + author=' ', + author_email=' ', + keywords='web pyramid pylons', + packages=find_packages(), + include_package_data=True, + install_requires=requires, + entry_points={ + 'paste.app_factory': [ + 'main = todo:main', + ] + } +) +``` + +`entry_points` section near the end sets up entry points into the application that other services can use. This allows the `plaster_pastedeploy` package to access what will be the `main` function in the application for building an application object and serving it. (I'll circle back to this in a bit.) + +Thesection near the end sets up entry points into the application that other services can use. This allows thepackage to access what will be thefunction in the application for building an application object and serving it. (I'll circle back to this in a bit.) + +When you installed `pyramid`, you also gained a few Pyramid-specific shell commands; the main ones to pay attention to are `pserve` and `pshell`. `pserve` will take an INI-style configuration file specified as an argument and serve the application locally. `pshell` will also take a configuration file as an argument, but instead of serving the application, it'll open up a Python shell that is aware of the application and its internal configuration. + +The configuration file is pretty important, so it's worth a closer look. Pyramid can take its configuration from environment variables or a configuration file. To avoid too much confusion around what is where, in this tutorial you'll write most of your configuration in the configuration file, with only a select few, sensitive configuration parameters set in the virtual environment. + +Create a file called `config.ini` + +``` +[app:main] +use = egg:todo +pyramid.default_locale_name = en + +[server:main] +use = egg:waitress#main +listen = localhost:6543 +``` + +This says a couple of things: + + * The actual application will come from the `main` function located in the `todo` package installed in the environment + * To serve this app, use the `waitress` package installed in the environment and serve on localhost port 6543 + + + +When serving an application and working in development, it helps to set up logging so you can see what's going on. The following configuration will handle logging for the application: + +``` +# continuing on... +[loggers] +keys = root, todo + +[handlers] +keys = console + +[formatters] +keys = generic + +[logger_root] +level = INFO +handlers = console + +[logger_todo] +level = DEBUG +handlers = +qualname = todo + +[handler_console] +class = StreamHandler +args = (sys.stderr,) +level = NOTSET +formatter = generic + +[formatter_generic] +format = %(asctime)s %(levelname)-5.5s [%(name)s:%(lineno)s][%(threadName)s] %(message)s +``` + +In short, this configuration asks to log everything to do with the application to the console. If you want less output, set the logging level to `WARN` so a message will fire only if there's a problem. + +Because Pyramid is meant for an application that grows, plan out a file structure that could support that growth. Web applications can, of course, be built however you want. In general, the conceptual blocks you'll want to cover will contain: + + * **Models** for containing the code and logic for dealing with data representations + * **Views** for code and logic pertaining to the request-response cycle + * **Routes** for the paths for access to the functionality of your application + * **Scripts** for any code that might be used in configuration or management of the application itself + + + +Given the above, the file structure can look like so: + +``` +setup.py +config.ini +todo/ + __init__.py + models.py + routes.py + views.py + scripts/ +``` + +Much like Flask's `app` object, Pyramid has its own central configuration. It comes from its `config` module and is known as the `Configurator` object. This object will handle everything from route configuration to pointing to where models and views exist. All this is done in an inner directory called `todo` within an `__init__.py` file. + +``` +# todo/__init__.py + +from pyramid.config import Configurator + +def main(global_config, **settings): + """Returns a Pyramid WSGI application.""" + config = Configurator(settings=settings) + config.scan() + return config.make_wsgi_app() +``` + +The `main` function looks for some global configuration from your environment as well as any settings that came through the particular configuration file you provide when you run the application. It takes those settings and uses them to build an instance of the `Configurator` object, which (for all intents and purposes) is the factory for your application. Finally, `config.scan()` looks for any views you'd like to attach to your application that are marked as Pyramid views. + +Wow, that was a lot to configure. + +### Using routes and views + +Now that a chunk of the configuration is done, you can start adding functionality to the application. Functionality comes in the form of URL routes that external clients can hit, which then map to functions that Python can run. + +With Pyramid, all functionality must be added to the `Configurator` in some way, shape, or form. For example, say you want to build the same simple `hello_world` view that you built with Flask, mapping to the route of `/`. With Pyramid, you can register the `/` route with the `Configurator` using the `.add_route()` method. This method takes as arguments the name of the route that you want to add as well as the actual pattern that must be matched to access that route. For this case, add the following to your `Configurator`: + +``` +config.add_route('home', '/') +``` + +Until you create a view and attach it to that route, that path into your application sits open and alone. When you add the view, make sure to include the `request` object in the parameter list. Every Pyramid view must have the `request` object as its first parameter, as that's what's being passed as the first argument to the view when it's called by Pyramid. + +One similarity that Pyramid views share with Flask is that you can mark a function as a view with a decorator. Specifically, the `@view_config` decorator from `pyramid.view`. + +In `views.py`, build the view that you want to see in the world. + +``` +from pyramid.view import view_config + +@view_config(route_name="hello", renderer="string") +def hello_world(request): + """Print 'Hello, world!' as the response body.""" + return 'Hello, world!' +``` + +With the `@view_config` decorator, you have to at least specify the name of the route that will map to this particular view. You can stack `view_config` decorators on top of one another to map to multiple routes if you want, but you have to have at least one to connect view the view at all, and each one must include the name of a route. **[NOTE: Is "to connect view the view" phrased correctly?]** + +The other argument, `renderer`, is optional but not really. If you don't specify a renderer, you have to deliberately construct the HTTP response you want to send back to the client using the `Response` object from `pyramid.response`. By specifying the `renderer` as a string, Pyramid knows to take whatever is returned by this function and wrap it in that same `Response` object with the MIME type of `text/plain`. By default, Pyramid allows you to use `string` and `json` as renderers. If you've attached a templating engine to your application because you want to have Pyramid generate your HTML as well, you can point directly to your HTML template as your renderer. + +The first view is done. Here's what `__init__.py` looks like now with the attached route. + +``` +# in __init__.py +from pyramid.config import Configurator + +def main(global_config, **settings): + """Returns a Pyramid WSGI application.""" + config = Configurator(settings=settings) + config.add_route('hello', '/') + config.scan() + return config.make_wsgi_app() +``` + +Spectacular! Getting here was no easy feat, but now that you're set up, you can add functionality with significantly less difficulty. + +### Smoothing a rough edge + +Right now the application only has one route, but it's easy to see that a large application can have many dozens or even hundreds of routes. Containing them all in the same `main` function with your central configuration isn't really the best idea, because it would become cluttered. Thankfully, it's fairly easy to include routes with a few tweaks to the application. + +**One** : In the `routes.py` file, create a function called `includeme` (yes, it must actually be named this) that takes a configurator object as an argument. + +``` +# in routes.py +def includeme(config): + """Include these routes within the application.""" +``` + +**Two** : Move the `config.add_route` method call from `__init__.py` into the `includeme` function: + +``` +def includeme(config): + """Include these routes within the application.""" + config.add_route('hello', '/') +``` + +**Three** : Alert the Configurator that you need to include this `routes.py` file as part of its configuration. Because it's in the same directory as `__init__.py`, you can get away with specifying the import path to this file as `.routes`. + +``` +# in __init__.py +from pyramid.config import Configurator + +def main(global_config, **settings): + """Returns a Pyramid WSGI application.""" + config = Configurator(settings=settings) + config.include('.routes') + config.scan() + return config.make_wsgi_app() +``` + +### Connecting the database + +As with Flask, you'll want to persist data by connecting a database. Pyramid will leverage [SQLAlchemy][6] directly instead of using a specially tailored package. + +First get the easy part out of the way. `psycopg2` and `sqlalchemy` are required to talk to the Postgres database and manage the models, so add them to `setup.py`. + +``` +# in setup.py +requires = [ + 'pyramid', + 'pyramid-ipython', + 'waitress', + 'sqlalchemy', + 'psycopg2' +] +# blah blah other code +``` + +Now, you have a decision to make about how you'll include the database's URL. There's no wrong answer here; what you do will depend on the application you're building and how public your codebase needs to be. + +The first option will keep as much configuration in one place as possible by hard-coding the database URL into the `config.ini` file. One drawback is this creates a security risk for applications with a public codebase. Anyone who can view the codebase will be able to see the full database URL, including username, password, database name, and port. Another is maintainability; if you needed to change environments or the application's database location, you'd have to modify the `config.ini` file directly. Either that or you'll have to maintain one configuration file for each new environment, which adds the potential for discontinuity and errors in the application. **If you choose this option** , modify the `config.ini` file under the `[app:main]` heading to include this key-value pair: + +``` +sqlalchemy.url = postgres://localhost:5432/pyramid_todo +``` + +The second option specifies the location of the database URL when you create the `Configurator`, pointing to an environment variable whose value can be set depending on the environment where you're working. One drawback is that you're further splintering the configuration, with some in the `config.ini` file and some directly in the Python codebase. Another drawback is that when you need to use the database URL anywhere else in the application (e.g., in a database management script), you have to code in a second reference to that same environment variable (or set up the variable in one place and import from that location). **If you choose this option** , add the following: + +``` +# in __init__.py +import os +from pyramid.config import Configurator + +SQLALCHEMY_URL = os.environ.get('DATABASE_URL', '') + +def main(global_config, **settings): + """Returns a Pyramid WSGI application.""" + settings['sqlalchemy.url'] = SQLALCHEMY_URL # <-- important! + config = Configurator(settings=settings) + config.include('.routes') + config.scan() + return config.make_wsgi_app() +``` + +### Defining objects + +OK, so now you have a database. Now you need `Task` and `User` objects. + +Because it uses SQLAlchemy directly, Pyramid differs somewhat from Flash on how objects are built. First, every object you want to construct must inherit from SQLAlchemy's [declarative base class][7]. It'll keep track of everything that inherits from it, enabling simpler management of the database. + +``` +# in models.py +from sqlalchemy.ext.declarative import declarative_base + +Base = declarative_base() + +class Task(Base): + pass + +class User(Base): + pass +``` + +The columns, data types for those columns, and model relationships will be declared in much the same way as with Flask, although they'll be imported directly from SQLAlchemy instead of some pre-constructed `db` object. Everything else is the same. + +``` +# in models.py +from datetime import datetime +import secrets + +from sqlalchemy import ( + Column, Unicode, Integer, DateTime, Boolean, relationship +) +from sqlalchemy.ext.declarative import declarative_base + +Base = declarative_base() + +class Task(Base): + """Tasks for the To Do list.""" + id = Column(Integer, primary_key=True) + name = Column(Unicode, nullable=False) + note = Column(Unicode) + creation_date = Column(DateTime, nullable=False) + due_date = Column(DateTime) + completed = Column(Boolean, default=False) + user_id = Column(Integer, ForeignKey('user.id'), nullable=False) + user = relationship("user", back_populates="tasks") + + def __init__(self, *args, **kwargs): + """On construction, set date of creation.""" + super().__init__(*args, **kwargs) + self.creation_date = datetime.now() + +class User(Base): + """The User object that owns tasks.""" + id = Column(Integer, primary_key=True) + username = Column(Unicode, nullable=False) + email = Column(Unicode, nullable=False) + password = Column(Unicode, nullable=False) + date_joined = Column(DateTime, nullable=False) + token = Column(Unicode, nullable=False) + tasks = relationship("Task", back_populates="user") + + def __init__(self, *args, **kwargs): + """On construction, set date of creation.""" + super().__init__(*args, **kwargs) + self.date_joined = datetime.now() + self.token = secrets.token_urlsafe(64) +``` + +Note that there's no `config.include` line for `models.py` anywhere because it's not needed. A `config.include` line is needed only if some part of the application's configuration needs to be changed. This has only created two objects, inheriting from some `Base` class that SQLAlchemy gave us. + +### Initializing the database + +Now that the models are done, you can write a script to talk to and initialize the database. In the `scripts` directory, create two files: `__init__.py` and `initializedb.py`. The first is simply to turn the `scripts` directory into a Python package. The second is the script needed for database management. + +`initializedb.py` needs a function to set up the necessary tables in the database. Like with Flask, this script must be aware of the `Base` object, whose metadata keeps track of every class that inherits from it. The database URL is required to point to and modify its tables. + +As such, this database initialization script will work: + +``` +# initializedb.py +from sqlalchemy import engine_from_config +from todo import SQLALCHEMY_URL +from todo.models import Base + +def main(): + settings = {'sqlalchemy.url': SQLALCHEMY_URL} + engine = engine_from_config(settings, prefix='sqlalchemy.') + if bool(os.environ.get('DEBUG', '')): + Base.metadata.drop_all(engine) + Base.metadata.create_all(engine) +``` + +**Important note:** This will work only if you include the database URL as an environment variable in `todo/__init__.py` (the second option above). If the database URL was stored in the configuration file, you'll have to include a few lines to read that file. It will look something like this: + +``` +# alternate initializedb.py +from pyramid.paster import get_appsettings +from pyramid.scripts.common import parse_vars +from sqlalchemy import engine_from_config +import sys +from todo.models import Base + +def main(): + config_uri = sys.argv[1] + options = parse_vars(sys.argv[2:]) + settings = get_appsettings(config_uri, options=options) + engine = engine_from_config(settings, prefix='sqlalchemy.') + if bool(os.environ.get('DEBUG', '')): + Base.metadata.drop_all(engine) + Base.metadata.create_all(engine) +``` + +Either way, in `setup.py`, add a console script that will access and run this function. + +``` +# bottom of setup.py +setup( + # ... other stuff + entry_points={ + 'paste.app_factory': [ + 'main = todo:main', + ], + 'console_scripts': [ + 'initdb = todo.scripts.initializedb:main', + ], + } +) +``` + +When this package is installed, you'll have access to a new console script called `initdb`, which will construct the tables in your database. If the database URL is stored in the configuration file, you'll have to include the path to that file when you invoke the command. It'll look like `$ initdb /path/to/config.ini`. + +### Handling requests and the database + +Ok, here's where it gets a little deep. Let's talk about **transactions**. A "transaction," in an abstract sense, is any change made to an existing database. As with Flask, transactions are persisted no sooner than when they are committed. If changes have been made that haven't yet been committed, and you don't want those to occur (maybe there's an error thrown in the process), you can **rollback** a transaction and abort those changes. + +In Python, the [transaction package][8] allows you to interact with transactions as objects, which can roll together multiple changes into one single commit. `transaction` provides **transaction managers** , which give applications a straightforward, thread-aware way of handling transactions so all you need to think about is what to change. The `pyramid_tm` package will take the transaction manager from `transaction` and wire it up in a way that's appropriate for Pyramid's request-response cycle, attaching a transaction manager to every incoming request. + +Normally, with Pyramid the `request` object is populated when the route mapping to a view is accessed and the view function is called. Every view function will have a `request` object to work with**.** However, Pyramid allows you to modify its configuration to add whatever you might need to the `request` object. You can use the transaction manager that you'll be adding to the `request` to create a session with every request and add that session to the request. + +Yay, so why is this important? + +By attaching a transaction-managed session to the `request` object, when the view finishes processing the request, any changes made to the database session will be committed without you needing to explicitly commit**.** Here's what all these concepts look like in code. + +``` +# __init__.py +import os +from pyramid.config import Configurator +from sqlalchemy import engine_from_config +from sqlalchemy.orm import sessionmaker +import zope.sqlalchemy + +SQLALCHEMY_URL = os.environ.get('DATABASE_URL', '') + +def get_session_factory(engine): + """Return a generator of database session objects.""" + factory = sessionmaker() + factory.configure(bind=engine) + return factory + +def get_tm_session(session_factory, transaction_manager): + """Build a session and register it as a transaction-managed session.""" + dbsession = session_factory() + zope.sqlalchemy.register(dbsession, transaction_manager=transaction_manager) + return dbsession + +def main(global_config, **settings): + """Returns a Pyramid WSGI application.""" + settings['sqlalchemy.url'] = SQLALCHEMY_URL + settings['tm.manager_hook'] = 'pyramid_tm.explicit_manager' + config = Configurator(settings=settings) + config.include('.routes') + config.include('pyramid_tm') + session_factory = get_session_factory(engine_from_config(settings, prefix='sqlalchemy.')) + config.registry['dbsession_factory'] = session_factory + config.add_request_method( + lambda request: get_tm_session(session_factory, request.tm), + 'dbsession', + reify=True + ) + + config.scan() + return config.make_wsgi_app() +``` + +That looks like a lot, but it only did was what was explained above, plus it added an attribute to the `request` object called `request.dbsession`. + +A few new packages were included here, so update `setup.py` with those packages. + +``` +# in setup.py +requires = [ + 'pyramid', + 'pyramid-ipython', + 'waitress', + 'sqlalchemy', + 'psycopg2', + 'pyramid_tm', + 'transaction', + 'zope.sqlalchemy' +] +# blah blah other stuff +``` + +### Revisiting routes and views + +You need to make some real views that handle the data within the database and the routes that map to them. + +Start with the routes. You created the `routes.py` file to handle your routes but didn't do much beyond the basic `/` route. Let's fix that. + +``` +# routes.py +def includeme(config): + config.add_route('info', '/api/v1/') + config.add_route('register', '/api/v1/accounts') + config.add_route('profile_detail', '/api/v1/accounts/{username}') + config.add_route('login', '/api/v1/accounts/login') + config.add_route('logout', '/api/v1/accounts/logout') + config.add_route('tasks', '/api/v1/accounts/{username}/tasks') + config.add_route('task_detail', '/api/v1/accounts/{username}/tasks/{id}') +``` + +Now, it not only has static URLs like `/api/v1/accounts`, but it can handle some variable URLs like `/api/v1/accounts/{username}/tasks/{id}` where any variable in a URL will be surrounded by curly braces. + +To create the view to create an individual task in your application (like in the Flash example), you can use the `@view_config` decorator to ensure that it only takes incoming `POST` requests and check out how Pyramid handles data from the client. + +Take a look at the code, then check out how it differs from Flask's version. + +``` +# in views.py +from datetime import datetime +from pyramid.view import view_config +from todo.models import Task, User + +INCOMING_DATE_FMT = '%d/%m/%Y %H:%M:%S' + +@view_config(route_name="tasks", request_method="POST", renderer='json') +def create_task(request): + """Create a task for one user.""" + response = request.response + response.headers.extend({'Content-Type': 'application/json'}) + user = request.dbsession.query(User).filter_by(username=request.matchdict['username']).first() + if user: + due_date = request.json['due_date'] + task = Task( + name=request.json['name'], + note=request.json['note'], + due_date=datetime.strptime(due_date, INCOMING_DATE_FMT) if due_date else None, + completed=bool(request.json['completed']), + user_id=user.id + ) + request.dbsession.add(task) + response.status_code = 201 + return {'msg': 'posted'} +``` + +To start, note on the `@view_config` decorator that the only type of request you want this view to handle is a "POST" request. If you want to specify one type of request or one set of requests, provide either the string noting the request or a tuple/list of such strings. + +``` +response = request.response +response.headers.extend({'Content-Type': 'application/json'}) +# ...other code... +response.status_code = 201 +``` + +The HTTP response sent to the client is generated based on `request.response`. Normally, you wouldn't have to worry about that object. It would just produce a properly formatted HTTP response and you'd never know the difference. However, because you want to do something specific, like modify the response's status code and headers, you need to access that response and its methods/attributes. + +Unlike with Flask, you don't need to modify the view function parameter list just because you have variables in the route URL. Instead, any time a variable exists in the route URL, it is collected in the `matchdict` attribute of the `request`. It will exist there as a key-value pair, where the key will be the variable (e.g., "username") and the value will be whatever value was specified in the route (e.g., "bobdobson"). Regardless of what value is passed in through the route URL, it'll always show up as a string in the `matchdict`. So, when you want to pull the username from the incoming request URL, access it with `request.matchdict['username']` + +``` +user = request.dbsession.query(User).filter_by(username=request.matchdict['username']).first() +``` + +Querying for objects when using `sqlalchemy` directly differs significantly from what the `flask-sqlalchemy` package allows. Recall that when you used `flask-sqlalchemy` to build your models, the models inherited from the `db.Model` object. That `db` object already contained a connection to the database, so that connection could perform a straightforward operation like `User.query.all()`. + +That simple interface isn't present here, as the models in the Pyramid app inherit from `Base`, which is generated from `declarative_base()`, coming directly from the `sqlalchemy` package. It has no direct awareness of the database it'll be accessing. That awareness was attached to the `request` object via the app's central configuration as the `dbsession` attribute. Here's the code from above that did that: + +``` +config.add_request_method( + lambda request: get_tm_session(session_factory, request.tm), + 'dbsession', + reify=True +) +``` + +With all that said, whenever you want to query OR modify the database, you must work through `request.dbsession`. In the case, you want to query your "users" table for a specific user by using their username as their identifier. As such, the `User` object is provided as an argument to the `.query` method, then the normal SQLAlchemy operations are done from there. + +An interesting thing about this way of querying the database is that you can query for more than just one object or list of one type of object. You can query for: + + * Object attributes on their own, e.g., `request.dbsession.query(User.username)` would query for usernames + * Tuples of object attributes, e.g., `request.dbsession.query(User.username, User.date_joined)` + * Tuples of multiple objects, e.g., `request.dbsession.query(User, Task)` + + + +The data sent along with the incoming request will be found within the `request.json` dictionary. + +The last major difference is, because of all the machinations necessary to attach the committing of a session's activity to Pyramid's request-response cycle, you don't have to call `request.dbsession.commit()` at the end of your view. It's convenient, but there is one thing to be aware of moving forward. If instead of a new add to the database, you wanted to edit a pre-existing object in the database, you couldn't use `request.dbsession.commit()`. Pyramid will throw an error, saying something along the lines of "commit behavior is being handled by the transaction manager, so you can't call it on your own." And if you don't do something that resembles committing your changes, your changes won't stick. + +The solution here is to use `request.dbsession.flush()`. The job of `.flush()` is to signal to the database that some changes have been made and need to be included with the next commit. + +### Planning for the future + +At this point, you've set up most of the important parts of Pyramid, analogous to what you constructed with Flask in part one. There's much more that goes into an application, but much of the meat is handled here. Other view functions will follow similar formatting, and of course, there's always the question of security (which Pyramid has built in!). + +One of the major differences I see in the setup of a Pyramid application is that it has a much more intense configuration step than there is with Flask. I broke down those configuration steps to explain more about what's going on when a Pyramid application is constructed. However, it'd be disingenuous to act like I've known all of this since I started programming. My first experience with the Pyramid framework was with Pyramid 1.7 and its scaffolding system of `pcreate`, which builds out most of the necessary configuration, so all you need to do is think about the functionality you want to build. + +As of Pyramid 1.8, `pcreate` has been deprecated in favor of [cookiecutter][9], which effectively does the same thing. The difference is that it's maintained by someone else, and there are cookiecutter templates for more than just Pyramid projects. Now that we've gone through the components of a Pyramid project, I'd never endorse building a Pyramid project from scratch again when a cookiecutter template is available. Why do the hard work if you don't have to? In fact, the [pyramid-cookiecutter-alchemy][10] template would accomplish much of what I've written here (and a little bit more). It's actually similar to the `pcreate` scaffold I used when I first learned Pyramid. + +Learn more Python at [PyCon Cleveland 2018][11]. + +-------------------------------------------------------------------------------- + +via: https://opensource.com/article/18/5/pyramid-framework + +作者：[Nicholas Hunt-Walker][a] +选题：[lujun9972][b] +译者：[译者ID](https://github.com/译者ID) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]: https://opensource.com/users/nhuntwalker +[b]: https://github.com/lujun9972 +[1]: https://opensource.com/article/18/4/flask +[2]: http://flask.pocoo.org/ +[3]: https://trypyramid.com/ +[4]: http://www.tornadoweb.org/en/stable/ +[5]: https://www.djangoproject.com/ +[6]: https://www.sqlalchemy.org/ +[7]: http://docs.sqlalchemy.org/en/latest/orm/extensions/declarative/api.html#api-reference +[8]: http://zodb.readthedocs.io/en/latest/transactions.html +[9]: https://cookiecutter.readthedocs.io/en/latest/ +[10]: https://github.com/Pylons/pyramid-cookiecutter-alchemy +[11]: https://us.pycon.org/2018/ diff --git a/sources/tech/20180523 How to dual-boot Linux and Windows.md b/sources/tech/20180523 How to dual-boot Linux and Windows.md deleted file mode 100644 index 372097c866..0000000000 --- a/sources/tech/20180523 How to dual-boot Linux and Windows.md +++ /dev/null @@ -1,224 +0,0 @@ -translating by Auk7F7 -How to dual-boot Linux and Windows -====== - - - -Even though Linux is a great operating system with widespread hardware and software support, the reality is that sometimes you have to use Windows, perhaps due to key apps that won't run under Linux. Thankfully, dual-booting Windows and Linux is very straightforward—and I'll show you how to set it up, with Windows 10 and Ubuntu 18.04, in this article. - -Before you get started, make sure you've backed up your computer. Although the dual-boot setup process is not very involved, accidents can still happen. So take the time to back up your important files in case chaos theory comes into play. In addition to backing up your files, consider taking an image backup of the disk as well, though that's not required and can be a more advanced process. - -### Prerequisites - -To get started, you will need the following five items: - -#### 1\. Two USB flash drives (or DVD-Rs) - -I recommend installing Windows and Ubuntu via flash drives since they're faster than DVDs. It probably goes without saying, but creating bootable media erases everything on the flash drive. Therefore, make sure the flash drives are empty or contain data you don't care about losing. - -If your machine doesn't support booting from USB, you can create DVD media instead. Unfortunately, because no two computers seem to have the same DVD-burning software, I can't walk you through that process. However, if your DVD-burning application has an option to burn from an ISO image, that's the option you need. - -#### 2\. A Windows 10 license - -If Windows 10 came with your PC, the license will be built into the computer, so you don't need to worry about entering it during installation. If you bought the retail edition, you should have a product key, which you will need to enter during the installation process. - -#### 3\. Windows 10 Media Creation Tool - -Download and launch the Windows 10 [Media Creation Tool][1]. Once you launch the tool, it will walk you through the steps required to create the Windows media on a USB or DVD-R. Note: Even if you already have Windows 10 installed, it's a good idea to create bootable media anyway, just in case something goes wrong and you need to reinstall it. - -#### 4\. Ubuntu 18.04 installation media - -Download the [Ubuntu 18.04][2] ISO image. - -#### 5\. Etcher software (for making a bootable Ubuntu USB drive) - -For creating bootable media for any Linux distribution, I recommend [Etcher][3]. Etcher works on all three major operating systems (Linux, MacOS, and Windows) and is careful not to let you overwrite your current operating system partition. - -Once you have downloaded and launched Etcher, click Select image, and point it to the Ubuntu ISO you downloaded in step 4. Next, click Select drive to choose your flash drive, and click Flash! to start the process of turning a flash drive into an Ubuntu installer. (If you're using a DVD-R, use your computer's DVD-burning software instead.) - -### Install Windows and Ubuntu - -You should be ready to begin. At this point, you should have accomplished the following: - - * Backed up your important files - * Created Windows installation media - * Created Ubuntu installation media - - - -There are two ways of going about the installation. First, if you already have Windows 10 installed, you can have the Ubuntu installer resize the partition, and the installation will proceed in the empty space. Or, if you haven't installed Windows 10, install it on a smaller partition you can set up during the installation process. (I'll describe how to do that below.) The second way is preferred and less error-prone. There's a good chance you won't have any issues either way, but installing Windows manually and giving it a smaller partition, then installing Ubuntu, is the easiest way to go. - -If you already have Windows 10 on your computer, skip the following Windows installation instructions and proceed to Installing Ubuntu. - -#### Installing Windows - -Insert the Windows installation media you created into your computer and boot from it. How you do this depends on your computer, but most have a key you can press to initiate the boot menu. On a Dell PC for example, that key is F12. If the flash drive doesn't show up as an option, you may need to restart the computer. Sometimes it will show up only if you've inserted the media before turning on the computer. If you see a message like, "press any key to boot from the installation media," press a key. You should see the following screen. Select your language and keyboard style and click Next. - -![Windows setup][5] - -Click on Install now to start the Windows installer. - -On the next screen, it will ask for your product key. If you don't have one because Windows 10 came with your PC, select "I don't have a product key." It should automatically activate after the installation once it catches up with updates. If you do have a product key, type that in and click Next. - - -![Enter product key][7] - - -Select which version of Windows you want to install. If you have a retail copy, the label will tell you what version you have. Otherwise, it is typically located with the documentation that came with your computer. In most cases, it's going to be either Windows 10 Home or Windows 10 Pro. Most PCs that come with the Home edition have a label that simply reads "Windows 10," while Pro is clearly marked. - - -![Select Windows version][10] - - -Accept the license agreement by checking the box, then click Next. - - -![Accept license terms][12] - - -After accepting the agreement, you have two installation options available. Choose the second option, Custom: Install Windows only (advanced). - - -![Select type of Windows installation][14] - - -The next screen should show your current hard disk configuration. - - -![Hard drive configuration][16] - - -Your results will probably look different than mine. I have never used this hard disk before, so it's completely unallocated. You will probably see one or more partitions for your current operating system. Highlight each partition and remove it. - -At this point, your screen will show your entire disk as unallocated. To continue, create a new partition. - - -![Create a new partition][18] - - -Here you can see that I divided the drive in half (or close enough) by creating a partition of 81,920MB (which is close to half of 160GB). Give Windows at least 40GB, preferably 64GB or more. Leave the rest of the drive unallocated, as that's where you'll install Ubuntu later. - -Your results will look similar to this: - - -![Leaving a partition with unallocated space][20] - - -Confirm the partitioning looks good to you and click Next. Windows will begin installing. - - -![Installing Windows][22] - - -If your computer successfully boots into Windows, you're all set to move on to the next step. - -![Windows desktop][24] - - -#### Installing Ubuntu - -Whether it was already there or you worked through the steps above, at this point you should have Windows installed. Now use the Ubuntu installation media you created earlier to boot into Ubuntu. Go ahead and insert the media and boot your computer from it. Again, the exact sequence of keys to access the boot menu varies from one computer to another, so check your documentation if you're not sure. If all goes well, you see the following screen once the media finishes loading: - - -![Ubuntu installation welcome screen][26] - - -Here, you can select between Try Ubuntu or Install Ubuntu. Don't install just yet; instead, click Try Ubuntu. After it finishes loading, you should see the Ubuntu desktop. - - -![Ubuntu desktop][28] - -By clicking Try Ubuntu, you have opted to try out Ubuntu before you install it. Here, in Live mode, you can play around with Ubuntu and make sure everything works before you commit to the installation. Ubuntu works with most PC hardware, but it's always better to test it out beforehand. Make sure you can access the internet and get audio and video playback. Going to YouTube and playing a video is a good way of doing all of that at once. If you need to connect to a wireless network, click on the networking icon at the top-right of the screen. There, you can find a list of wireless networks and connect to yours. - -Once you're ready to go, double-click on the Install Ubuntu 18.04 LTS icon on the desktop to launch the installer. - -Choose the language you want to use for the installation process, then click Continue. - - -![Select language in Ubuntu][30] - - -Next, choose the keyboard layout. Once you've made your selection, click Continue. - - -![Select keyboard in Ubuntu][32] - -You have a few options on the screen below. One, you can choose a Normal or a Minimal installation. For most people, the Normal installation is ideal. Advanced users may want to do a Minimal install instead, which has fewer software applications installed by default. In addition, you can choose to download updates and whether or not to include third-party software and drivers. I recommend checking both of those boxes. When done, click Continue. - - -![Choose Ubuntu installation options][34] - -The next screen asks whether you want to erase the disk or set up a dual-boot. Since you're dual-booting, choose Install Ubuntu alongside Windows 10. Click Install Now. - - -![install Ubuntu alongside Windows][36] - - -The following screen may appear. If you installed Windows from scratch and left unallocated space on the disk, Ubuntu will automatically set itself up in the empty space, so you won't see this screen. If you already had Windows 10 installed and it's taking up the entire drive, this screen will appear and give you an option to select a disk at the top. If you have just one disk, you can choose how much space to steal from Windows and apply to Ubuntu. You can drag the vertical line in the middle left and right with your mouse to take space away from one and gives it to the other. Adjust this exactly the way you want it, then click Install Now. - - -![Allocate drive space][38] - - -You should see a confirmation screen indicating what Ubuntu plans on doing. If everything looks right, click Continue. - -Ubuntu is now installing in the background. You still have some configuration to do, though. While Ubuntu tries its best to figure out your location, you can click on the map to narrow it down to ensure your time zone and other things are set correctly. - -Next, fill in the user account information: your name, computer name, username, and password. Click Continue when you're done. - -There you have it! The installation is complete. Go ahead and reboot the PC. - -If all went according to plan, you should see a screen similar to this when your computer restarts. Choose Ubuntu or Windows 10; the other options are for troubleshooting, so I won't go into them. - -Try booting into both Ubuntu and Windows to test them out and make sure everything works as expected. If it does, you now have both Windows and Ubuntu installed on your computer. - --------------------------------------------------------------------------------- - -via: https://opensource.com/article/18/5/dual-boot-linux - -作者：[Jay LaCroix][a] -选题：[lujun9972](https://github.com/lujun9972) -译者：[译者ID](https://github.com/译者ID) -校对：[校对者ID](https://github.com/校对者ID) - -本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 - -[a]:https://opensource.com/users/jlacroix -[1]:https://www.microsoft.com/en-us/software-download/windows10 -[2]:https://www.ubuntu.com/download/desktop -[3]:http://www.etcher.io -[4]:/file/397066 -[5]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_01.png (Windows setup) -[6]:/file/397076 -[7]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_03.png (Enter product key) -[8]:data:image/gif;base64,R0lGODlhAQABAPABAP///wAAACH5BAEKAAAALAAAAAABAAEAAAICRAEAOw== (Click and drag to move) -[9]:/file/397081 -[10]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_04.png (Select Windows version) -[11]:/file/397086 -[12]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_05.png (Accept license terms) -[13]:/file/397091 -[14]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_06.png (Select type of Windows installation) -[15]:/file/397096 -[16]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_07.png (Hard drive configuration) -[17]:/file/397101 -[18]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_08.png (Create a new partition) -[19]:/file/397106 -[20]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_09.png (Leaving a partition with unallocated space) -[21]:/file/397111 -[22]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_10.png (Installing Windows) -[23]:/file/397116 -[24]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_11.png (Windows desktop) -[25]:/file/397121 -[26]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_12.png (Ubuntu installation welcome screen) -[27]:/file/397126 -[28]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_13.png (Ubuntu desktop) -[29]:/file/397131 -[30]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_15.png (Select language in Ubuntu) -[31]:/file/397136 -[32]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_16.png (Select keyboard in Ubuntu) -[33]:/file/397141 -[34]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_17.png (Choose Ubuntu installation options) -[35]:/file/397146 -[36]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_18.png (Install Ubuntu alongside Windows) -[37]:/file/397151 -[38]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_18b.png (Allocate drive space) diff --git a/sources/tech/20180525 How to Set Different Wallpaper for Each Monitor in Linux.md b/sources/tech/20180525 How to Set Different Wallpaper for Each Monitor in Linux.md deleted file mode 100644 index 386149400c..0000000000 --- a/sources/tech/20180525 How to Set Different Wallpaper for Each Monitor in Linux.md +++ /dev/null @@ -1,89 +0,0 @@ -How to Set Different Wallpaper for Each Monitor in Linux -====== -**Brief: If you want to display different wallpapers on multiple monitors on Ubuntu 18.04 or any other Linux distribution with GNOME, MATE or Budgie desktop environment, this nifty tool will help you achieve this.** - -Multi-monitor setup often leads to multiple issues on Linux but I am not going to discuss those issues in this article. I have rather a positive article on multiple monitor support on Linux. - -If you are using multiple monitor, perhaps you would like to setup a different wallpaper for each monitor. I am not sure about other Linux distributions and desktop environments, but Ubuntu with [GNOME desktop][1] doesn’t provide this functionality on its own. - -Fret not! In this quick tutorial, I’ll show you how to set a different wallpaper for each monitor on Linux distributions with GNOME desktop environment. - -### Setting up different wallpaper for each monitor on Ubuntu 18.04 and other Linux distributions - -![Different wallaper on each monitor in Ubuntu][2] - -I am going to use a nifty tool called [HydraPaper][3] for setting different backgrounds on different monitors. HydraPaper is a [GTK][4] based application to set different backgrounds for each monitor in [GNOME desktop environment][5]. - -It also supports on [MATE][6] and [Budgie][7] desktop environments. Which means Ubuntu MATE and [Ubuntu Budgie][8] users can also benefit from this application. - -#### Install HydraPaper on Linux using FlatPak - -HydraPaper can be installed easily using [FlatPak][9]. Ubuntu 18.04 already provides support for FlatPaks so all you need to do is to download the application file and double click on it to open it with the GNOME Software Center. - -You can refer to this article to learn [how to enable FlatPak support][10] on your distribution. Once you have the FlatPak support enabled, just download it from [FlatHub][11] and install it. - -[Download HydraPaper][12] - -#### Using HydraPaper for setting different background on different monitors - -Once installed, just look for HydraPaper in application menu and start the application. You’ll see images from your Pictures folder here because by default the application takes images from the Pictures folder of the user. - -You can add your own folder(s) where you keep your wallpapers. Do note that it doesn’t find images recursively. If you have nested folders, it will only show images from the top folder. - -![Setting up different wallpaper for each monitor on Linux][13] - -Using HydraPaper is absolutely simple. Just select the wallpapers for each monitor and click on the apply button at the top. You can easily identify external monitor(s) termed with HDMI. - -![Setting up different wallpaper for each monitor on Linux][14] - -You can also add selected wallpapers to ‘Favorites’ for quick access. Doing this will move the ‘favorite wallpapers’ from Wallpapers tab to Favorites tab. - -![Setting up different wallpaper for each monitor on Linux][15] - -You don’t need to start HydraPaper at each boot. Once you set different wallpaper for different monitor, the settings are saved and you’ll see your chosen wallpapers even after restart. This would be expected behavior of course but I thought I would mention the obvious. - -One big downside of HydraPaper is in the way it is designed to work. You see, HydraPaper combines your selected wallpapers into one single image and stretches it across the screens giving an impression of having different background on each display. And this becomes an issue when you remove the external display. - -For example, when I tried using my laptop without the external display, it showed me an background image like this. - -![Dual Monitor wallpaper HydraPaper][16] - -Quite obviously, this is not what I would expect. - -#### Did you like it? - -HydraPaper makes setting up different backgrounds on different monitors a painless task. It supports more than two monitors and monitors with different orientation. Simple interface with only the required features makes it an ideal application for those who always use dual monitors. - -How do you set different wallpaper for different monitor on Linux? Do you think HydraPaper is an application worth installing? - -Do share your views and if you find this article, please share it on various social media channels such as Twitter and [Reddit][17]. - --------------------------------------------------------------------------------- - -via: https://itsfoss.com/wallpaper-multi-monitor/ - -作者：[Abhishek Prakash][a] -选题：[lujun9972](https://github.com/lujun9972) -译者：[译者ID](https://github.com/译者ID) -校对：[校对者ID](https://github.com/校对者ID) - -本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 - -[a]: https://itsfoss.com/author/abhishek/ -[1]:https://www.gnome.org/ -[2]:https://4bds6hergc-flywheel.netdna-ssl.com/wp-content/uploads/2018/05/multi-monitor-wallpaper-setup-800x450.jpeg -[3]:https://github.com/GabMus/HydraPaper -[4]:https://www.gtk.org/ -[5]:https://itsfoss.com/gnome-tricks-ubuntu/ -[6]:https://mate-desktop.org/ -[7]:https://budgie-desktop.org/home/ -[8]:https://itsfoss.com/ubuntu-budgie-18-review/ -[9]:https://flatpak.org -[10]:https://flatpak.org/setup/ -[11]:https://flathub.org -[12]:https://flathub.org/apps/details/org.gabmus.hydrapaper -[13]:https://4bds6hergc-flywheel.netdna-ssl.com/wp-content/uploads/2018/05/different-wallpaper-each-monitor-hydrapaper-2-800x631.jpeg -[14]:https://4bds6hergc-flywheel.netdna-ssl.com/wp-content/uploads/2018/05/different-wallpaper-each-monitor-hydrapaper-1.jpeg -[15]:https://4bds6hergc-flywheel.netdna-ssl.com/wp-content/uploads/2018/05/different-wallpaper-each-monitor-hydrapaper-3.jpeg -[16]:https://4bds6hergc-flywheel.netdna-ssl.com/wp-content/uploads/2018/05/hydra-paper-dual-monitor-800x450.jpeg -[17]:https://www.reddit.com/r/LinuxUsersGroup/ diff --git a/sources/tech/20180614 An introduction to the Tornado Python web app framework.md b/sources/tech/20180614 An introduction to the Tornado Python web app framework.md new file mode 100644 index 0000000000..9c9e5c9500 --- /dev/null +++ b/sources/tech/20180614 An introduction to the Tornado Python web app framework.md @@ -0,0 +1,590 @@ +[#]: collector: (lujun9972) +[#]: translator: ( ) +[#]: reviewer: ( ) +[#]: publisher: ( ) +[#]: subject: (An introduction to the Tornado Python web app framework) +[#]: via: (https://opensource.com/article/18/6/tornado-framework) +[#]: author: (Nicholas Hunt-Walker https://opensource.com/users/nhuntwalker) +[#]: url: ( ) + +An introduction to the Tornado Python web app framework +====== +In the third part in a series comparing Python frameworks, learn about Tornado, built to handle asynchronous processes. + + +In the first two articles in this four-part series comparing different Python web frameworks, we've covered the [Pyramid][1] and [Flask][2] web frameworks. We've built the same app twice and seen the similarities and differences between a complete DIY framework and a framework with a few more batteries included. + +Now let's look at a somewhat different option: [the Tornado framework][3]. Tornado is, for the most part, as bare-bones as Flask, but with a major difference: Tornado is built specifically to handle asynchronous processes. That special sauce isn't terribly useful in the app we're building in this series, but we'll see where we can use it and how it works in a more general situation. + +Let's continue the pattern we set in the first two articles and start by tackling the setup and config. + +### Tornado startup and configuration + +If you've been following along with this series, what we do first shouldn't come as much of a surprise. + +``` +$ mkdir tornado_todo +$ cd tornado_todo +$ pipenv install --python 3.6 +$ pipenv shell +(tornado-someHash) $ pipenv install tornado +``` + +Create a `setup.py` for installing our application: + +``` +(tornado-someHash) $ touch setup.py +# setup.py +from setuptools import setup, find_packages + +requires = [ + 'tornado', + 'tornado-sqlalchemy', + 'psycopg2', +] + +setup( + name='tornado_todo', + version='0.0', + description='A To-Do List built with Tornado', + author=' ', + author_email=' ', + keywords='web tornado', + packages=find_packages(), + install_requires=requires, + entry_points={ + 'console_scripts': [ + 'serve_app = todo:main', + ], + }, +) +``` + +Because Tornado doesn't require any external configuration, we can dive right into writing the Python code that'll run our application. Let's make our inner `todo` directory and fill it with the first few files we'll need. + +``` +todo/ + __init__.py + models.py + views.py +``` + +Like Flask and Pyramid, Tornado has some central configuration that will go in `__init__.py`. From `tornado.web`, we'll import the `Application` object. This will handle the hookups for routing and views, including our database (when we get there) and any extra settings needed to run our Tornado app. + +``` +# __init__.py +from tornado.httpserver import HTTPServer +from tornado.options import define, options +from tornado.web import Application + +define('port', default=8888, help='port to listen on') + +def main(): + """Construct and serve the tornado application.""" + app = Application() + http_server = HTTPServer(app) + http_server.listen(options.port) +``` + +When we use the `define` function, we end up creating attributes on the `options` object. Anything that goes in the position of the first argument will be the attribute's name, and what's assigned to the `default` keyword argument will be the value of that attribute. + +As an example, if we name the attribute `potato` instead of `port`, we can access its value via `options.potato`. + +Calling `listen` on the `HTTPServer` doesn't start the server yet. We must do one more step to have a working application that can listen for requests and return responses. We need an input-output loop. Thankfully, Tornado comes with that out of the box in the form of `tornado.ioloop.IOLoop`. + +``` +# __init__.py +from tornado.httpserver import HTTPServer +from tornado.ioloop import IOLoop +from tornado.options import define, options +from tornado.web import Application + +define('port', default=8888, help='port to listen on') + +def main(): + """Construct and serve the tornado application.""" + app = Application() + http_server = HTTPServer(app) + http_server.listen(options.port) + print('Listening on http://localhost:%i' % options.port) + IOLoop.current().start() +``` + +I like some kind of a `print` statement somewhere that tells me when I'm serving my application, but that's me. You could do without the `print` line if you so chose. + +We begin our I/O loop with `IOLoop.current().start()`. Let's talk a little more about input, output, and asynchronicity. + +### The basics of async in Python and the I/O loop + +Allow me to preface by saying that I am absolutely, positively, surely, and securely not an expert in asynchronous programming. As with all things I write, what follows stems from the limits of my understanding of the concept. As I am human, it may be deeply, deeply flawed. + +The main concerns of an asynchronous program are: + + * How is data coming in? + * How is data going out? + * When can some procedure be left to run without consuming my full attention? + + + +Due to the [global interpreter lock][4] (GIL), Python is—by design—a [single-threaded][5] language. For every task a Python program must execute, the full attention of its thread of execution is on that task for the duration of that task. Our HTTP server is written in Python. Thus, when data (e.g., an HTTP request) is received, the server's sole focus is that incoming data. This means that, in most cases, whatever procedures need to run in handling and processing that data will completely consume your server's thread of execution, blocking other potential data from being received until your server finishes whatever it needed to do. + +In many cases this isn't too problematic; a typical web request-response cycle will take only fractions of a second. Along with that, the sockets that HTTP servers are built from can maintain a backlog of incoming requests to be handled. So, if a request comes in while that socket is handling something else, chances are it'll just wait in line a bit before being addressed. For a low to intermediate traffic site, a fraction of a second isn't that big of a deal, and you can use multiple deployed instances along with a load-balancer like [NGINX][6] to distribute traffic for the larger request loads. + +What if, however, your average response time takes more than a fraction of a second? What if you use data from the incoming request to start some long-running process like a machine-learning algorithm or some massive database query? Now, your single-threaded web server starts to accumulate an unaddressable backlog of requests, some of which will get dropped due to simply timing out. This is not an option, especially if you want your service to be seen as reliable on a regular basis. + +In comes the asynchronous Python program. It's important to keep in mind that because it's written in Python, the program is still a single-threaded process. Anything that would block execution in a synchronous program, unless specifically flagged, will still block execution in an asynchronous one. + +When it's structured correctly, however, your asynchronous Python program can "shelve" long-running tasks whenever you designate that a certain function should have the ability to do so. Your async controller can then be alerted when the shelved tasks are complete and ready to resume, managing their execution only when needed without completely blocking the handling of new input. + +That was somewhat jargony, so let's demonstrate with a human example. + +#### Bringing it home + +I often find myself trying to get multiple chores done at home with little time to do them. On a given day, that backlog of chores may look like: + + * Cook a meal (20 min. prep, 40 min. cook) + * Wash dishes (60 min.) + * Wash and dry laundry (30 min. wash, 90 min. dry per load) + * Vacuum floors (30 min.) + + + +If I were acting as a traditional, synchronous program, I'd be doing each task myself, by hand. Each task would require my full attention to complete before I could consider handling anything else, as nothing would get done without my active attention. So my sequence of execution might look like: + + 1. Focus fully on preparing and cooking the meal, including waiting around for food to just… cook (60 min.). + 2. Transfer dirty dishes to sink (65 min. elapsed). + 3. Wash all the dishes (125 min. elapsed). + 4. Start laundry with my full focus on that, including waiting around for the washing machine to finish, then transferring laundry to the dryer, and waiting for the dryer to finish (250 min. elapsed). + 5. Vacuum the floors (280 min. elapsed). + + + +That's 4 hours and 40 minutes to complete my chores from end-to-end. + +Instead of working hard, I should work smart like an asynchronous program. My home is full of machines that can do my work for me without my continuous effort. Meanwhile, I can switch my attention to what may actively need it right now. + +My execution sequence might instead look like: + + 1. Load clothes into and start the washing machine (5 min.). + 2. While the washing machine is running, prep food (25 min. elapsed). + 3. After prepping food, start cooking food (30 min. elapsed). + 4. While the food is cooking, move clothes from the washing machine into the dryer and start dryer (35 min. elapsed). + 5. While dryer is running and food is still cooking, vacuum the floors (65 min. elapsed). + 6. After vacuuming the floors, take food off the stove and load the dishwasher (70 min. elapsed). + 7. Run the dishwasher (130 min. when done). + + + +Now I'm down to 2 hours and 10 minutes. Even if I allow more time for switching between jobs (10-20 more minutes total), I'm still down to about half the time I would've spent if I'd waited to perform each task in sequential order. This is the power of structuring your program to be asynchronous. + +#### So where does the I/O loop come in? + +An asynchronous Python program works by taking in data from some external source (input) and, should the process require it, offloading that data to some external worker (output) for processing. When that external process finishes, the main Python program is alerted. The program then picks up the result of that external processing (input) and continues on its merry way. + +Whenever that data isn't actively in the hands of the main Python program, that main program is freed to work on just about anything else. This includes awaiting completely new inputs (e.g., HTTP requests) and handling the results of long-running processes (e.g., results of machine-learning algorithms, long-running database queries). The main program, while still single-threaded, becomes event-driven, triggered into action for specific occurrences handled by the program. The main worker that listens for those events and dictates how they should be handled is the I/O loop. + +We traveled a long road to get to this nugget of an explanation, I know, but what I'm hoping to communicate here is that it's not magic, nor is it some type of complex parallel processing or multi-threaded work. The global interpreter lock is still in place; any long-running process within the main program will still block anything else from happening. The program is also still single-threaded; however, by externalizing tedious work, we conserve the attention of that thread to only what it needs to be attentive to. + +This is kind of like my asynchronous chores above. When my attention is fully necessary for prepping food, that's all I'm doing. However, when I can get the stove to do work for me by cooking my food, and the dishwasher to wash my dishes, and the washing machine and dryer to handle my laundry, my attention is freed to work on other things. When I am alerted that one of my long-running tasks is finished and ready to be handled once again, if my attention is free, I can pick up the results of that task and do whatever needs to be done with it next. + +### Tornado routes and views + +Despite having gone through all the trouble of talking about async in Python, we're going to hold off on using it for a bit and first write a basic Tornado view. + +Unlike the function-based views we've seen in the Flask and Pyramid implementations, Tornado's views are all class-based. This means we'll no longer use individual, standalone functions to dictate how requests are handled. Instead, the incoming HTTP request will be caught and assigned to be an attribute of our defined class. Its methods will then handle the corresponding request types. + +Let's start with a basic view that prints "Hello, World" to the screen. Every class-based view we construct for our Tornado app must inherit from the `RequestHandler` object found in `tornado.web`. This will set up all the ground-level logic that we'll need (but don't want to write) to take in a request and construct a properly formatted HTTP response. + +``` +from tornado.web import RequestHandler + +class HelloWorld(RequestHandler): + """Print 'Hello, world!' as the response body.""" + + def get(self): + """Handle a GET request for saying Hello World!.""" + self.write("Hello, world!") +``` + +Because we're looking to handle a `GET` request, we declare (really override) the `get` method. Instead of returning anything, we provide text or a JSON-serializable object to be written to the response body with `self.write`. After that, we let the `RequestHandler` take on the rest of the work that must be done before a response can be sent. + +As it stands, this view has no actual connection to the Tornado application itself. We have to go back into `__init__.py` and update the `main` function a bit. Here's the new hotness: + +``` +# __init__.py +from tornado.httpserver import HTTPServer +from tornado.ioloop import IOLoop +from tornado.options import define, options +from tornado.web import Application +from todo.views import HelloWorld + +define('port', default=8888, help='port to listen on') + +def main(): + """Construct and serve the tornado application.""" + app = Application([ + ('/', HelloWorld) + ]) + http_server = HTTPServer(app) + http_server.listen(options.port) + print('Listening on http://localhost:%i' % options.port) + IOLoop.current().start() +``` + +#### What'd we do? + +We imported the `HelloWorld` view from the `views.py` file into `__init__.py` at the top of the script. Then we added a list of route-view pairs as the first argument to the instantiation to `Application`. Whenever we want to declare a route in our application, it must be tied to a view. You can use the same view for multiple routes if you want, but there must always be a view for every route. + +We can make sure this all works by running our app with the `serve_app` command we enabled in the `setup.py`. Check `http://localhost:8888/` and see that it says "Hello, world!" + +Of course, there's more we can and will do in this space, but let's move on to models. + +### Connecting the database + +If we want to hold onto data, we need to connect a database. Like with Flask, we'll be using a framework-specific variant of SQLAlchemy called [tornado-sqlalchemy][7]. + +Why use this instead of just the bare [SQLAlchemy][8]? Well, `tornado-sqlalchemy` has all the goodness of straightforward SQLAlchemy, so we can still declare models with a common `Base` as well as use all the column data types and relationships to which we've grown accustomed. Alongside what we already know from habit, `tornado-sqlalchemy` provides an accessible async pattern for its database-querying functionality specifically to work with Tornado's existing I/O loop. + +We set the stage by adding `tornado-sqlalchemy` and `psycopg2` to `setup.py` to the list of required packages and reinstall the package. In `models.py`, we declare our models. This step looks pretty much exactly like what we've already seen in Flask and Pyramid, so I'll skip the full-class declarations and just put up the necessaries of the `Task` model. + +``` +# this is not the complete models.py, but enough to see the differences +from tornado_sqlalchemy import declarative_base + +Base = declarative_base + +class Task(Base): + # and so on, because literally everything's the same... +``` + +We still have to connect `tornado-sqlalchemy` to the actual application. In `__init__.py`, we'll be defining the database and integrating it into the application. + +``` +# __init__.py +from tornado.httpserver import HTTPServer +from tornado.ioloop import IOLoop +from tornado.options import define, options +from tornado.web import Application +from todo.views import HelloWorld + +# add these +import os +from tornado_sqlalchemy import make_session_factory + +define('port', default=8888, help='port to listen on') +factory = make_session_factory(os.environ.get('DATABASE_URL', '')) + +def main(): + """Construct and serve the tornado application.""" + app = Application([ + ('/', HelloWorld) + ], + session_factory=factory + ) + http_server = HTTPServer(app) + http_server.listen(options.port) + print('Listening on http://localhost:%i' % options.port) + IOLoop.current().start() +``` + +Much like the session factory we passed around in Pyramid, we can use `make_session_factory` to take in a database URL and produce an object whose sole purpose is to provide connections to the database for our views. We then tie it into our application by passing the newly created `factory` into the `Application` object with the `session_factory` keyword argument. + +Finally, initializing and managing the database will look the same as it did for Flask and Pyramid (i.e., separate DB management script, working with respect to the `Base` object, etc.). It'll look so similar that I'm not going to reproduce it here. + +### Revisiting views + +Hello, World is always nice for learning the basics, but we need some real, application-specific views. + +Let's start with the info view. + +``` +# views.py +import json +from tornado.web import RequestHandler + +class InfoView(RequestHandler): + """Only allow GET requests.""" + SUPPORTED_METHODS = ["GET"] + + def set_default_headers(self): + """Set the default response header to be JSON.""" + self.set_header("Content-Type", 'application/json; charset="utf-8"') + + def get(self): + """List of routes for this API.""" + routes = { + 'info': 'GET /api/v1', + 'register': 'POST /api/v1/accounts', + 'single profile detail': 'GET /api/v1/accounts/ ', + 'edit profile': 'PUT /api/v1/accounts/ ', + 'delete profile': 'DELETE /api/v1/accounts/ ', + 'login': 'POST /api/v1/accounts/login', + 'logout': 'GET /api/v1/accounts/logout', + "user's tasks": 'GET /api/v1/accounts/ /tasks', + "create task": 'POST /api/v1/accounts/ /tasks', + "task detail": 'GET /api/v1/accounts/ /tasks/ ', + "task update": 'PUT /api/v1/accounts/ /tasks/ ', + "delete task": 'DELETE /api/v1/accounts/ /tasks/ ' + } + self.write(json.dumps(routes)) +``` + +So what changed? Let's go from the top down. + +The `SUPPORTED_METHODS` class attribute was added. This will be an iterable of only the request methods that are accepted by this view. Any other method will return a [405][9] status code. When we made the `HelloWorld` view, we didn't specify this, mostly out of laziness. Without this class attribute, this view would respond to any request trying to access the route tied to the view. + +The `set_default_headers` method is declared, which sets the default headers of the outgoing HTTP response. We declare this here to ensure that any response we send back has a `"Content-Type"` of `"application/json"`. + +We added `json.dumps(some_object)` to the argument of `self.write` because it makes it easy to construct the content for the body of the outgoing response. + +Now that's done, and we can go ahead and connect it to the home route in `__init__.py`. + +``` +# __init__.py +from tornado.httpserver import HTTPServer +from tornado.ioloop import IOLoop +from tornado.options import define, options +from tornado.web import Application +from todo.views import InfoView + +# add these +import os +from tornado_sqlalchemy import make_session_factory + +define('port', default=8888, help='port to listen on') +factory = make_session_factory(os.environ.get('DATABASE_URL', '')) + +def main(): + """Construct and serve the tornado application.""" + app = Application([ + ('/', InfoView) + ], + session_factory=factory + ) + http_server = HTTPServer(app) + http_server.listen(options.port) + print('Listening on http://localhost:%i' % options.port) + IOLoop.current().start() +``` + +As we know, more views and routes will need to be written. Each one will get dropped into the `Application` route listing as needed. Each will also need a `set_default_headers` method. On top of that, we'll create our `send_response`method, whose job it will be to package our response along with any custom status codes we want to set for a given response. Since each one will need both methods, we can create a base class containing them that each of our views can inherit from. That way, we have to write them only once. + +``` +# views.py +import json +from tornado.web import RequestHandler + +class BaseView(RequestHandler): + """Base view for this application.""" + + def set_default_headers(self): + """Set the default response header to be JSON.""" + self.set_header("Content-Type", 'application/json; charset="utf-8"') + + def send_response(self, data, status=200): + """Construct and send a JSON response with appropriate status code.""" + self.set_status(status) + self.write(json.dumps(data)) +``` + +For a view like the `TaskListView` we'll soon write, we'll also need a connection to the database. We'll need `tornado_sqlalchemy`'s `SessionMixin` to add a database session within every view class. We can fold that into the `BaseView` so that, by default, every view inheriting from it has access to a database session. + +``` +# views.py +import json +from tornado_sqlalchemy import SessionMixin +from tornado.web import RequestHandler + +class BaseView(RequestHandler, SessionMixin): + """Base view for this application.""" + + def set_default_headers(self): + """Set the default response header to be JSON.""" + self.set_header("Content-Type", 'application/json; charset="utf-8"') + + def send_response(self, data, status=200): + """Construct and send a JSON response with appropriate status code.""" + self.set_status(status) + self.write(json.dumps(data)) +``` + +As long as we're modifying this `BaseView` object, we should address a quirk that will come up when we consider data being posted to this API. + +When Tornado (as of v.4.5) consumes data from a client and organizes it for use in the application, it keeps all the incoming data as bytestrings. However, all the code here assumes Python 3, so the only strings that we want to work with are Unicode strings. We can add another method to this `BaseView` class whose job it will be to convert the incoming data to Unicode before using it anywhere else in the view. + +If we want to convert this data before we use it in a proper view method, we can override the view class's native `prepare` method. Its job is to run before the view method runs. If we override the `prepare` method, we can set some logic to run that'll do the bytestring-to-Unicode conversion whenever a request is received. + +``` +# views.py +import json +from tornado_sqlalchemy import SessionMixin +from tornado.web import RequestHandler + +class BaseView(RequestHandler, SessionMixin): + """Base view for this application.""" + + def prepare(self): + self.form_data = { + key: [val.decode('utf8') for val in val_list] + for key, val_list in self.request.arguments.items() + } + + def set_default_headers(self): + """Set the default response header to be JSON.""" + self.set_header("Content-Type", 'application/json; charset="utf-8"') + + def send_response(self, data, status=200): + """Construct and send a JSON response with appropriate status code.""" + self.set_status(status) + self.write(json.dumps(data)) +``` + +If there's any data coming in, it'll be found within the `self.request.arguments` dictionary. We can access that data by key and convert its contents (always a list) to Unicode. Because this is a class-based view instead of a function-based view, we can store the modified data as an instance attribute to be used later. I called it `form_data` here, but it can just as easily be called `potato`. The point is that we can store data that has been submitted to the application. + +### Asynchronous view methods + +Now that we've built our `BaseView`, we can build the `TaskListView` that will inherit from it. + +As you can probably tell from the section heading, this is where all that talk about asynchronicity comes in. The `TaskListView` will handle `GET` requests for returning a list of tasks and `POST` requests for creating new tasks given some form data. Let's first look at the code to handle the `GET` request. + +``` +# all the previous imports +import datetime +from tornado.gen import coroutine +from tornado_sqlalchemy import as_future +from todo.models import Profile, Task + +# the BaseView is above here +class TaskListView(BaseView): + """View for reading and adding new tasks.""" + SUPPORTED_METHODS = ("GET", "POST",) + + @coroutine + def get(self, username): + """Get all tasks for an existing user.""" + with self.make_session() as session: + profile = yield as_future(session.query(Profile).filter(Profile.username == username).first) + if profile: + tasks = [task.to_dict() for task in profile.tasks] + self.send_response({ + 'username': profile.username, + 'tasks': tasks + }) +``` + +The first major piece here is the `@coroutine` decorator, imported from `tornado.gen`. Any Python callable that has a portion that acts out of sync with the normal flow of the call stack is effectively a "co-routine"; a routine that can run alongside other routines. In the example of my household chores, pretty much every chore was a co-routine. Some were blocking routines (e.g., vacuuming the floor), but that routine simply blocked my ability to start or attend to anything else. It didn't block any of the other routines that were already set in motion from continuing. + +Tornado offers a number of ways to build an app that take advantage of co-routines, including allowing us to set locks on function calls, conditions for synchronizing asynchronous routines, and a system for manually modifying the events that control the I/O loop. + +The only way the `@coroutine` decorator is used here is to allow the `get` method to farm out the SQL query as a background process and resume once the query is complete, while not blocking the Tornado I/O loop from handling other sources of incoming data. That is all that's "asynchronous" about this implementation: out-of-band database queries. Clearly if we wanted to showcase the magic and wonder of an async web app, a To-Do List isn't the way. + +But hey, that's what we're building, so let's see how our method takes advantage of that `@coroutine` decorator. The `SessionMixin` that was, well, mixed into the `BaseView` declaration added two handy, database-aware attributes to our view class: `session` and `make_session`. They're similarly named and accomplish fairly similar goals. + +The `self.session` attribute is a session with an eye on the database. At the end of the request-response cycle, just before the view sends a response back to the client, any changes that have been made to the database are committed, and the session is closed. + +`self.make_session` is a context manager and generator, building and returning a brand new session object on the fly. That first `self.session` object still exists; `make_session` creates a new one anyway. The `make_session` generator also has baked into itself the logic for committing and closing the session it creates as soon as its context (i.e., indentation level) ends. + +If you inspect the source code, there is no difference between the type of object assigned to `self.session` and the type of object generated by `self.make_session`. The difference is in how they're managed. + +With the `make_session` context manager, the generated session belongs only to the context, beginning and ending within that context. You can open, modify, commit, and close multiple database sessions within the same view with the `make_session` context manager. + +`self.session` is much simpler, with the session already opened by the time you get to your view method and committing before the response is sent back to the client. + +Although the [read the docs snippet][10] and the [the PyPI example][11] both specify the use of the context manager, there's nothing about either the `self.session` object or the `session` generated by `self.make_session` that is inherently asynchronous. The point where we start thinking about the async behavior built into `tornado-sqlalchemy` comes when we initiate a query. + +The `tornado-sqlalchemy` package provides us with the `as_future` function. The job of `as_future` is to wrap the query constructed by the `tornado-sqlalchemy` session and yield its return value. If the view method is decorated with `@coroutine`, then using this `yield as_future(query)` pattern will now make your wrapped query an asynchronous background process. The I/O loop takes over, awaiting the return value of the query and the resolution of the `future` object created by `as_future`. + +To have access to the result from `as_future(query)`, you must `yield` from it. Otherwise, you get only an unresolved generator object and can do nothing with the query. + +Everything else in this view method is pretty much par for the course, mirroring what we've already seen in Flask and Pyramid. + +The `post` method will look fairly similar. For the sake of consistency, let's see how the `post` method looks and how it handles the `self.form_data` that was constructed with the `BaseView`. + +``` +@coroutine +def post(self, username): + """Create a new task.""" + with self.make_session() as session: + profile = yield as_future(session.query(Profile).filter(Profile.username == username).first) + if profile: + due_date = self.form_data['due_date'][0] + task = Task( + name=self.form_data['name'][0], + note=self.form_data['note'][0], + creation_date=datetime.now(), + due_date=datetime.strptime(due_date, '%d/%m/%Y %H:%M:%S') if due_date else None, + completed=self.form_data['completed'][0], + profile_id=profile.id, + profile=profile + ) + session.add(task) + self.send_response({'msg': 'posted'}, status=201) +``` + +As I said, it's about what we'd expect: + + * The same query pattern as we saw with the `get` method + * The construction of an instance of a new `Task` object, populated with data from `form_data` + * The adding (but not committing because it's handled by the context manager!) of the new `Task` object to the database session + * The sending of a response back to the client + + + +And thus we have the basis for our Tornado web app. Everything else (e.g., database management and more views for a more complete app) is effectively the same as what we've already seen in the Flask and Pyramid apps. + +### Thoughts about using the right tool for the right job + +What we're starting to see as we continue to move through these web frameworks is that they can all effectively handle the same problems. For something like this To-Do List, any framework can do the job. However, some web frameworks are more appropriate for certain jobs than other ones, depending on what "more appropriate" means for you and your needs. + +While Tornado is clearly capable of handling the same job that Pyramid or Flask can handle, to use it for an app like this is effectively a waste. It's like using a car to travel one block from home. Yes it can do the job of "travel," but short trips aren't why you choose to use a car over a bike or just your feet. + +Per the documentation, Tornado is billed as "a Python web framework and asynchronous networking library." There are few like it in the Python web framework ecosystem. If the job you're trying to accomplish requires (or would benefit significantly from) asynchronicity in any way, shape, or form, use Tornado. If your application needs to handle multiple, long-lived connections while not sacrificing much in performance, choose Tornado. If your application is many applications in one and needs to be thread-aware for the accurate handling of data, reach for Tornado. That's where it works best. + +Use your car to do "car things." Use other modes of transportation to do everything else. + +### Going forward and a little perspective check + +Speaking of using the right tool for the right job, keep in mind the scope and scale, both present and future, of your application when choosing your framework. Up to this point we've only looked at frameworks meant for small to midsized web applications. The next and final installment of this series will cover one of the most popular Python frameworks, Django, meant for big applications that might grow bigger. Again, while it technically can and will handle the To-Do List problem, keep in mind that it's not really what the framework is for. We'll still put it through its paces to show how an application can be built with it, but we have to keep in mind the intent of the framework and how that's reflected in its architecture: + + * **Flask:** Meant for small, simple projects; makes it easy for us to construct views and connect them to routes quickly; can be encapsulated in a single file without much fuss + * **Pyramid:** Meant for projects that may grow; contains a fair bit of configuration to get up and running; separate realms of application components can easily be divided and built out to arbitrary depth without losing sight of the central application + * **Tornado:** Meant for projects benefiting from precise and deliberate I/O control; allows for co-routines and easily exposes methods that can control how requests are received/responses are sent and when those operations occur + * **Django:** (As we'll see) meant for big things that may get bigger; large ecosystem of add-ons and mods; very opinionated in its configuration and management in order to keep all the disparate parts in line + + + +Whether you've been reading since the first post in this series or joined a little later, thanks for reading! Please feel free to leave questions or comments. I'll see you next time with hands full of Django. + +### Huge shout-out to the Python BDFL + +I must give credit where credit is due. Massive thanks are owed to [Guido van Rossum][12] for more than just creating my favorite programming language. + +During [PyCascades 2018][13], I was fortunate not only to give the talk this article series is based on, but also to be invited to the speakers' dinner. I got to sit next to Guido the whole night and pepper him with questions. One of those questions was how in the world async worked in Python, and he, without a bit of fuss, spent time explaining it to me in a way that I could start to grasp the concept. He later [tweeted to me][14] a spectacular resource for learning async with Python that I subsequently read three times over three months, then wrote this post. You're an awesome guy, Guido! + +-------------------------------------------------------------------------------- + +via: https://opensource.com/article/18/6/tornado-framework + +作者：[Nicholas Hunt-Walker][a] +选题：[lujun9972][b] +译者：[译者ID](https://github.com/译者ID) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]: https://opensource.com/users/nhuntwalker +[b]: https://github.com/lujun9972 +[1]: https://opensource.com/article/18/5/pyramid-framework +[2]: https://opensource.com/article/18/4/flask +[3]: https://tornado.readthedocs.io/en/stable/ +[4]: https://realpython.com/python-gil/ +[5]: https://en.wikipedia.org/wiki/Thread_(computing) +[6]: https://www.nginx.com/ +[7]: https://tornado-sqlalchemy.readthedocs.io/en/latest/ +[8]: https://www.sqlalchemy.org/ +[9]: https://en.wikipedia.org/wiki/List_of_HTTP_status_codes#4xx_Client_errors +[10]: https://tornado-sqlalchemy.readthedocs.io/en/latest/#usage +[11]: https://pypi.org/project/tornado-sqlalchemy/#description +[12]: https://www.twitter.com/gvanrossum +[13]: https://www.pycascades.com +[14]: https://twitter.com/gvanrossum/status/956186585493458944 diff --git a/sources/tech/20180707 Version Control Before Git with CVS.md b/sources/tech/20180707 Version Control Before Git with CVS.md deleted file mode 100644 index 4c59a2cfc0..0000000000 --- a/sources/tech/20180707 Version Control Before Git with CVS.md +++ /dev/null @@ -1,313 +0,0 @@ -（translating by runningwater) -Version Control Before Git with CVS -====== -Github was launched in 2008. If your software engineering career, like mine, is no older than Github, then Git may be the only version control software you have ever used. While people sometimes grouse about its steep learning curve or unintuitive interface, Git has become everyone’s go-to for version control. In Stack Overflow’s 2015 developer survey, 69.3% of respondents used Git, almost twice as many as used the second-most-popular version control system, Subversion. After 2015, Stack Overflow stopped asking developers about the version control systems they use, perhaps because Git had become so popular that the question was uninteresting. - -Git itself is not much older than Github. Linus Torvalds released the first version of Git in 2005. Though today younger developers might have a hard time conceiving of a world where the term “version control software” didn’t more or less just mean Git, such a world existed not so long ago. There were lots of alternatives to choose from. Open source developers preferred Subversion, enterprises and video game companies used Perforce (some still do), while the Linux kernel project famously relied on a version control system called BitKeeper. - -Some of these systems, particularly BitKeeper, might feel familiar to a young Git user transported back in time. Most would not. BitKeeper aside, the version control systems that came before Git worked according to a fundamentally different paradigm. In a taxonomy offered by Eric Sink, author of Version Control by Example, Git is a third-generation version control system, while most of Git’s predecessors, the systems popular in the 1990s and early 2000s, are second-generation version control systems. Where third-generation version control systems are distributed, second-generation version control systems are centralized. You have almost certainly heard Git described as a “distributed” version control system before. I never quite understood the distributed/centralized distinction, at least not until I installed and experimented with a centralized second-generation version control system myself. - -The system I installed was CVS. CVS, short for Concurrent Versions System, was the very first second-generation version control system. It was also the most popular version control system for about a decade until it was replaced in 2000 by Subversion. Even then, Subversion was supposed to be “CVS but better,” which only underscores how dominant CVS had become throughout the 1990s. - -CVS was first developed in 1986 by a Dutch computer scientist named Dick Grune, who was looking for a way to collaborate with his students on a compiler project. CVS was initially little more than a collection of shell scripts wrapping RCS (Revision Control System), a first-generation version control system that Grune wanted to improve. RCS works according to a pessimistic locking model, meaning that no two programmers can work on a single file at once. In order to edit a file, you have to first ask RCS for an exclusive lock on the file, which you keep until you are finished editing. If someone else is already editing a file you need to edit, you have to wait. CVS improved on RCS and ushered in the second generation of version control systems by trading the pessimistic locking model for an optimistic one. Programmers could now edit the same file at the same time, merging their edits and resolving any conflicts later. (Brian Berliner, an engineer who later took over the CVS project, wrote a very readable [paper][1] about CVS’ innovations in 1990.) - -In that sense, CVS wasn’t all that different from Git, which also works according to an optimistic model. But that’s where the similarities end. In fact, when Linus Torvalds was developing Git, one of his guiding principles was WWCVSND, or “What Would CVS Not Do.” Whenever he was in doubt about a decision, he strove to choose the option that had not been chosen in the design of CVS. So even though CVS predates Git by over a decade, it influenced Git as a kind of negative template. - -I’ve really enjoyed playing around with CVS. I think there’s no better way to understand why Git’s distributed nature is such an improvement on what came before. So I invite you to come along with me on an exciting journey and spend the next ten minutes of your life learning about a piece of software nobody has used in the last decade. (See correction.) - -### Getting Started with CVS - -Instructions for installing CVS can be found on the [project’s homepage][2]. On MacOS, you can install CVS using Homebrew. - -Since CVS is centralized, it distinguishes between the client-side universe and the server-side universe in a way that something like Git does not. The distinction is not so pronounced that there are different executables. But in order to start using CVS, even on your own machine, you’ll have to set up the CVS backend. - -The CVS backend, the central store for all your code, is called the repository. Whereas in Git you would typically have a repository for every project, in CVS the repository holds all of your projects. There is one central repository for everything, though there are ways to work with only a project at a time. - -To create a local repository, you run the `init` command. You would do this somewhere global like your home directory. - -``` -$ cvs -d ~/sandbox init -``` - -CVS allows you to pass options to either the `cvs` command itself or to the `init` subcommand. Options that appear after the `cvs` command are global in nature, while options that appear after the subcommand are specific to the subcommand. In this case, the `-d` flag is global. Here it happens to tell CVS where we want to create our repository, but in general the `-d` flag points to the location of the repository we want to use for any given action. It can be tedious to supply the `-d` flag all the time, so the `CVSROOT` environment variable can be set instead. - -Since we’re working locally, we’ve just passed a path for our `-d` argument, but we could also have included a hostname. - -The command creates a directory called `sandbox` in your home directory. If you list the contents of `sandbox`, you’ll find that it contains another directory called `CVSROOT`. This directory, not to be confused with the environment variable, holds administrative files for the repository. - -Congratulations! You’ve just created your first CVS repository. - -### Checking In Code - -Let’s say that you’ve decided to keep a list of your favorite colors. You are an artistically inclined but extremely forgetful person. You type up your list of colors and save it as a file called `favorites.txt`: - -``` -blue -orange -green - -definitely not yellow -``` - -Let’s also assume that you’ve saved your file in a new directory called `colors`. Now you’d like to put your favorite color list under version control, because fifty years from now it will be interesting to look back and see how your tastes changed through time. - -In order to do that, you will have to import your directory as a new CVS project. You can do that using the `import` command: - -``` -$ cvs -d ~/sandbox import -m "" colors colors initial -N colors/favorites.txt - -No conflicts created by this import -``` - -Here we are specifying the location of our repository with the `-d` flag again. The remaining arguments are passed to the `import` subcommand. We have to provide a message, but here we don’t really need one, so we’ve left it blank. The next argument, `colors`, specifies the name of our new directory in the repository; here we’ve just used the same name as the directory we are in. The last two arguments specify the vendor tag and the release tag respectively. We’ll talk more about tags in a minute. - -You’ve just pulled your “colors” project into the CVS repository. There are a couple different ways to go about bringing code into CVS, but this is the method recommended by [Pragmatic Version Control Using CVS][3], the Pragmatic Programmer book about CVS. What makes this method a little awkward is that you then have to check out your work fresh, even though you’ve already got an existing `colors` directory. Instead of using that directory, you’re going to delete it and then check out the version that CVS already knows about: - -``` -$ cvs -d ~/sandbox co colors -cvs checkout: Updating colors -U colors/favorites.txt -``` - -This will create a new directory, also called `colors`. In this directory you will find your original `favorites.txt` file along with a directory called `CVS`. The `CVS` directory is basically CVS’ equivalent of the `.git` directory in every Git repository. - -### Making Changes - -Get ready for a trip. - -Just like Git, CVS has a `status` subcommand: - -``` -$ cvs status -cvs status: Examining . -=================================================================== -File: favorites.txt Status: Up-to-date - - Working revision: 1.1.1.1 2018-07-06 19:27:54 -0400 - Repository revision: 1.1.1.1 /Users/sinclairtarget/sandbox/colors/favorites.txt,v - Commit Identifier: fD7GYxt035GNg8JA - Sticky Tag: (none) - Sticky Date: (none) - Sticky Options: (none) -``` - -This is where things start to look alien. CVS doesn’t have commit objects. In the above, there is something called a “Commit Identifier,” but this might be only a relatively recent edition—no mention of a “Commit Identifier” appears in Pragmatic Version Control Using CVS, which was published in 2003. (The last update to CVS was released in 2008.) - -Whereas with Git you’d talk about the version of a file associated with commit `45de392`, in CVS files are versioned separately. The first version of your file is version 1.1, the next version is 1.2, and so on. When branches are involved, extra numbers are appended, so you might end up with something like the `1.1.1.1` above, which appears to be the default in our case even though we haven’t created any branches. - -If you were to run `cvs log` (equivalent to `git log`) in a project with lots of files and commits, you’d see an individual history for each file. You might have a file at version 1.2 and a file at version 1.14 in the same project. - -Let’s go ahead and make a change to version 1.1 of our `favorites.txt` file: - -``` - blue - orange - green -+cyan - - definitely not yellow -``` - -Once we’ve made the change, we can run `cvs diff` to see what CVS thinks we’ve done: - -``` -$ cvs diff -cvs diff: Diffing . -Index: favorites.txt -=================================================================== -RCS file: /Users/sinclairtarget/sandbox/colors/favorites.txt,v -retrieving revision 1.1.1.1 -diff -r1.1.1.1 favorites.txt -3a4 -> cyan -``` - -CVS recognizes that we added a new line containing the color “cyan” to the file. (Actually, it says we’ve made changes to the “RCS” file; you can see that CVS never fully escaped its original association with RCS.) The diff we are being shown is the diff between the copy of `favorites.txt` in our working directory and the 1.1.1.1 version stored in the repository. - -In order to update the version stored in the repository, we have to commit the change. In Git, this would be a multi-step process. We’d have to stage the change so that it appears in our index. Then we’d commit the change. Finally, to make the change visible to anyone else, we’d have to push the commit up to the origin repository. - -In CVS, all of these things happen when you run `cvs commit`. CVS just bundles up all the changes it can find and puts them in the repository: - -``` -$ cvs commit -m "Add cyan to favorites." -cvs commit: Examining . -/Users/sinclairtarget/sandbox/colors/favorites.txt,v <-- favorites.txt -new revision: 1.2; previous revision: 1.1 -``` - -I’m so used to Git that this strikes me as terrifying. Without an opportunity to stage changes, any old thing that you’ve touched in your working directory might end up as part of the public repository. Did you passive-aggressively rewrite a coworker’s poorly implemented function out of cathartic necessity, never intending for him to know? Too bad, he now thinks you’re a dick. You also can’t edit your commits before pushing them, since a commit is a push. Do you enjoy spending 40 minutes repeatedly running `git rebase -i` until your local commit history flows like the derivation of a mathematical proof? Sorry, you can’t do that here, and everyone is going to find out that you don’t actually write your tests first. - -But I also now understand why so many people find Git needlessly complicated. If `cvs commit` is what you were used to, then I’m sure staging and pushing changes would strike you as a pointless chore. - -When people talk about Git being a “distributed” system, this is primarily the difference they mean. In CVS, you can’t make commits locally. A commit is a submission of code to the central repository, so it’s not something you can do without a connection. All you’ve got locally is your working directory. In Git, you have a full-fledged local repository, so you can make commits all day long even while disconnected. And you can edit those commits, revert, branch, and cherry pick as much as you want, without anybody else having to know. - -Since commits were a bigger deal, CVS users often made them infrequently. Commits would contain as many changes as today we might expect to see in a ten-commit pull request. This was especially true if commits triggered a CI build and an automated test suite. - -If we now run `cvs status`, we can see that we have a new version of our file: - -``` -$ cvs status -cvs status: Examining . -=================================================================== -File: favorites.txt Status: Up-to-date - - Working revision: 1.2 2018-07-06 21:18:59 -0400 - Repository revision: 1.2 /Users/sinclairtarget/sandbox/colors/favorites.txt,v - Commit Identifier: pQx5ooyNk90wW8JA - Sticky Tag: (none) - Sticky Date: (none) - Sticky Options: (none) -``` - -### Merging - -As mentioned above, in CVS you can edit a file that someone else is already editing. That was CVS’ big improvement on RCS. What happens when you need to bring your changes back together? - -Let’s say that you have invited some friends to add their favorite colors to your list. While they are adding their colors, you decide that you no longer like the color green and remove it from the list. - -When you go to commit your changes, you might discover that CVS notices a problem: - -``` -$ cvs commit -m "Remove green" -cvs commit: Examining . -cvs commit: Up-to-date check failed for `favorites.txt' -cvs [commit aborted]: correct above errors first! -``` - -It looks like your friends committed their changes first. So your version of `favorites.txt` is not up-to-date with the version in the repository. If you run `cvs status`, you’ll see that your local copy of `favorites.txt` is version 1.2 with some local changes, but the repository version is 1.3: - -``` -$ cvs status -cvs status: Examining . -=================================================================== -File: favorites.txt Status: Needs Merge - - Working revision: 1.2 2018-07-07 10:42:43 -0400 - Repository revision: 1.3 /Users/sinclairtarget/sandbox/colors/favorites.txt,v - Commit Identifier: 2oZ6n0G13bDaldJA - Sticky Tag: (none) - Sticky Date: (none) - Sticky Options: (none) -``` - -You can run `cvs diff` to see exactly what the differences between 1.2 and 1.3 are: - -``` -$ cvs diff -r HEAD favorites.txt -Index: favorites.txt -=================================================================== -RCS file: /Users/sinclairtarget/sandbox/colors/favorites.txt,v -retrieving revision 1.3 -diff -r1.3 favorites.txt -3d2 -< green -7,10d5 -< -< pink -< hot pink -< bubblegum pink -``` - -It seems that our friends really like pink. In any case, they’ve edited a different part of the file than we have, so the changes are easy to merge. CVS can do that for us when we run `cvs update`, which is similar to `git pull`: - -``` -$ cvs update -cvs update: Updating . -RCS file: /Users/sinclairtarget/sandbox/colors/favorites.txt,v -retrieving revision 1.2 -retrieving revision 1.3 -Merging differences between 1.2 and 1.3 into favorites.txt -M favorites.txt -``` - -If you now take a look at `favorites.txt`, you’ll find that it has been modified to include the changes that your friends made to the file. Your changes are still there too. Now you are free to commit the file: - -``` -$ cvs commit -cvs commit: Examining . -/Users/sinclairtarget/sandbox/colors/favorites.txt,v <-- favorites.txt -new revision: 1.4; previous revision: 1.3 -``` - -The end result is what you’d get in Git by running `git pull --rebase`. Your changes have been added on top of your friends’ changes. There is no “merge commit.” - -Sometimes, changes to the same file might be incompatible. If your friends had changed “green” to “olive,” for example, that would have conflicted with your change removing “green” altogether. In the early days of CVS, this was exactly the kind of case that caused people to worry that CVS wasn’t safe; RCS’ pessimistic locking ensured that such a case could never arise. But CVS guarantees safety by making sure that nobody’s changes get overwritten automatically. You have to tell CVS which change you want to keep going forward, so when you run `cvs update`, CVS marks up the file with both changes in the same way that Git does when Git detects a merge conflict. You then have to manually edit the file and pick the change you want to keep. - -The interesting thing to note here is that merge conflicts have to be fixed before you can commit. This is another consequence of CVS’ centralized nature. In Git, you don’t have to worry about resolving merges until you push the commits you’ve got locally. - -Since CVS doesn’t have easily addressable commit objects, the only way to group a collection of changes is to mark a particular working directory state with a tag. - -Creating a tag is easy: - -``` -$ cvs tag VERSION_1_0 -cvs tag: Tagging . -T favorites.txt -``` - -You’ll later be able to return files to this state by running `cvs update` and passing the tag to the `-r` flag: - -``` -$ cvs update -r VERSION_1_0 -cvs update: Updating . -U favorites.txt -``` - -Because you need a tag to rewind to an earlier working directory state, CVS encourages a lot of preemptive tagging. Before major refactors, for example, you might create a `BEFORE_REFACTOR_01` tag that you could later use if the refactor went wrong. People also used tags if they wanted to generate project-wide diffs. Basically, all the things we routinely do today with commit hashes have to be anticipated and planned for with CVS, since you needed to have the tags available already. - -Branches can be created in CVS, sort of. Branches are just a special kind of tag: - -``` -$ cvs rtag -b TRY_EXPERIMENTAL_THING colors -cvs rtag: Tagging colors -``` - -That only creates the branch (in full view of everyone, by the way), so you still need to switch to it using `cvs update`: - -``` -$ cvs update -r TRY_EXPERIMENTAL_THING -``` - -The above commands switch onto the new branch in your current working directory, but Pragmatic Version Control Using CVS actually advises that you create a new directory to hold your new branch. Presumably its authors found switching directories easier than switching branches in CVS. - -Pragmatic Version Control Using CVS also advises against creating branches off of an existing branch. They recommend only creating branches off of the mainline branch, which in Git is known as `master`. In general, branching was considered an “advanced” CVS skill. In Git, you might start a new branch for almost any trivial reason, but in CVS branching was typically used only when really necessary, such as for releases. - -A branch could later be merged back into the mainline using `cvs update` and the `-j` flag: - -``` -$ cvs update -j TRY_EXPERIMENTAL_THING -``` - -### Thanks for the Commit Histories - -In 2007, Linus Torvalds gave [a talk][4] about Git at Google. Git was very new then, so the talk was basically an attempt to persuade a roomful of skeptical programmers that they should use Git, even though Git was so different from anything then available. If you haven’t already seen the talk, I highly encourage you to watch it. Linus is an entertaining speaker, even if he never fails to be his brash self. He does an excellent job of explaining why the distributed model of version control is better than the centralized one. A lot of his criticism is reserved for CVS in particular. - -Git is a [complex tool][5]. Learning it can be a frustrating experience. But I’m also continually amazed at the things that Git can do. In comparison, CVS is simple and straightforward, though often unable to do many of the operations we now take for granted. Going back and using CVS for a while is an excellent way to find yourself with a new appreciation for Git’s power and flexibility. It illustrates well why understanding the history of software development can be so beneficial—picking up and re-examining obsolete tools will teach you volumes about the why behind the tools we use today. - -If you enjoyed this post, more like it come out every two weeks! Follow [@TwoBitHistory][6] on Twitter or subscribe to the [RSS feed][7] to make sure you know when a new post is out. - -#### Correction - -I’ve been told that there are many organizations, particularly risk-adverse organizations that do things like make medical device software, that still use CVS. Programmers in these organizations have developed little tricks for working around CVS’ limitations, such as making a new branch for almost every change to avoid committing directly to `HEAD`. (Thanks to Michael Kohne for pointing this out.) - --------------------------------------------------------------------------------- - -via: https://twobithistory.org/2018/07/07/cvs.html - -作者：[Two-Bit History][a] -选题：[lujun9972][b] -译者：[runningwater](https://github.com/runningwater) -校对：[校对者ID](https://github.com/校对者ID) - -本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 - -[a]: https://twobithistory.org -[b]: https://github.com/lujun9972 -[1]: https://docs.freebsd.org/44doc/psd/28.cvs/paper.pdf -[2]: https://www.nongnu.org/cvs/ -[3]: http://shop.oreilly.com/product/9780974514000.do -[4]: https://www.youtube.com/watch?v=4XpnKHJAok8 -[5]: https://xkcd.com/1597/ -[6]: https://twitter.com/TwoBitHistory -[7]: https://twobithistory.org/feed.xml diff --git a/sources/tech/20180709 5 Firefox extensions to protect your privacy.md b/sources/tech/20180709 5 Firefox extensions to protect your privacy.md deleted file mode 100644 index 848856fe07..0000000000 --- a/sources/tech/20180709 5 Firefox extensions to protect your privacy.md +++ /dev/null @@ -1,54 +0,0 @@ -5 Firefox extensions to protect your privacy -====== - - - -In the wake of the Cambridge Analytica story, I took a hard look at how far I had let Facebook penetrate my online presence. As I'm generally concerned about single points of failure (or compromise), I am not one to use social logins. I use a password manager and create unique logins for every site (and you should, too). - -What I was most perturbed about was the pervasive intrusion Facebook was having on my digital life. I uninstalled the Facebook mobile app almost immediately after diving into the Cambridge Analytica story. I also [disconnected all apps, games, and websites][1] from Facebook. Yes, this will change your experience on Facebook, but it will also protect your privacy. As a veteran with friends spread out across the globe, maintaining the social connectivity of Facebook is important to me. - -I went about the task of scrutinizing other services as well. I checked Google, Twitter, GitHub, and more for any unused connected applications. But I know that's not enough. I need my browser to be proactive in preventing behavior that violates my privacy. I began the task of figuring out how best to do that. Sure, I can lock down a browser, but I need to make the sites and tools I use work while trying to keep them from leaking data. - -Following are five tools that will protect your privacy while using your browser. The first three extensions are available for Firefox and Chrome, while the latter two are only available for Firefox. - -### Privacy Badger - -[Privacy Badger][2] has been my go-to extension for quite some time. Do other content or ad blockers do a better job? Maybe. The problem with a lot of content blockers is that they are "pay for play." Meaning they have "partners" that get whitelisted for a fee. That is the antithesis of why content blockers exist. Privacy Badger is made by the Electronic Frontier Foundation (EFF), a nonprofit entity with a donation-based business model. Privacy Badger promises to learn from your browsing habits and requires minimal tuning. For example, I have only had to whitelist a handful of sites. Privacy Badger also allows granular controls of exactly which trackers are enabled on what sites. It's my #1, must-install extension, no matter the browser. - -### DuckDuckGo Privacy Essentials - -The search engine DuckDuckGo has typically been privacy-conscious. [DuckDuckGo Privacy Essentials][3] works across major mobile devices and browsers. It's unique in the sense that it grades sites based on the settings you give them. For example, Facebook gets a D, even with Privacy Protection enabled. Meanwhile, [chrisshort.net][4] gets a B with Privacy Protection enabled and a C with it disabled. If you're not keen on EFF or Privacy Badger for whatever reason, I would recommend DuckDuckGo Privacy Essentials (choose one, not both, as they essentially do the same thing). - -### HTTPS Everywhere - -[HTTPS Everywhere][5] is another extension from the EFF. According to HTTPS Everywhere, "Many sites on the web offer some limited support for encryption over HTTPS, but make it difficult to use. For instance, they may default to unencrypted HTTP or fill encrypted pages with links that go back to the unencrypted site. The HTTPS Everywhere extension fixes these problems by using clever technology to rewrite requests to these sites to HTTPS." While a lot of sites and browsers are getting better about implementing HTTPS, there are a lot of sites that still need help. HTTPS Everywhere will try its best to make sure your traffic is encrypted. - -### NoScript Security Suite - -[NoScript Security Suite][6] is not for the faint of heart. While the Firefox-only extension "allows JavaScript, Java, Flash, and other plugins to be executed only by trusted websites of your choice," it doesn't do a great job at figuring out what your choices are. But, make no mistake, a surefire way to prevent leaking data is not executing code that could leak it. NoScript enables that via its "whitelist-based preemptive script blocking." This means you will need to build the whitelist as you go for sites not already on it. Note that NoScript is only available for Firefox. - -### Facebook Container - -[Facebook Container][7] makes Firefox the only browser where I will use Facebook. "Facebook Container works by isolating your Facebook identity into a separate container that makes it harder for Facebook to track your visits to other websites with third-party cookies." This means Facebook cannot snoop on activity happening elsewhere in your browser. Suddenly those creepy ads will stop appearing so frequently (assuming you uninstalled the Facebook app from your mobile devices). Using Facebook in an isolated space will prevent any additional collection of data. Remember, you've given Facebook data already, and Facebook Container can't prevent that data from being shared. - -These are my go-to extensions for browser privacy. What are yours? Please share them in the comments. - --------------------------------------------------------------------------------- - -via: https://opensource.com/article/18/7/firefox-extensions-protect-privacy - -作者：[Chris Short][a] -选题：[lujun9972](https://github.com/lujun9972) -译者：[译者ID](https://github.com/译者ID) -校对：[校对者ID](https://github.com/校对者ID) - -本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 - -[a]:https://opensource.com/users/chrisshort -[1]:https://www.facebook.com/help/211829542181913 -[2]:https://www.eff.org/privacybadger -[3]:https://duckduckgo.com/app -[4]:https://chrisshort.net -[5]:https://www.eff.org/https-everywhere -[6]:https://noscript.net/ -[7]:https://addons.mozilla.org/en-US/firefox/addon/facebook-container/ diff --git a/sources/tech/20180725 Build an interactive CLI with Node.js.md b/sources/tech/20180725 Build an interactive CLI with Node.js.md index f240e51efd..6ec13f1cfc 100644 --- a/sources/tech/20180725 Build an interactive CLI with Node.js.md +++ b/sources/tech/20180725 Build an interactive CLI with Node.js.md @@ -1,5 +1,3 @@ -translating by Flowsnow - Build an interactive CLI with Node.js ====== diff --git a/sources/tech/20180727 How to analyze your system with perf and Python.md b/sources/tech/20180727 How to analyze your system with perf and Python.md index 4573ed1ee0..c1be98cc0e 100644 --- a/sources/tech/20180727 How to analyze your system with perf and Python.md +++ b/sources/tech/20180727 How to analyze your system with perf and Python.md @@ -1,7 +1,3 @@ -**translating by [erlinux](https://github.com/erlinux)** -**PROJECT MANAGEMENT TOOL called [gn2.sh](https://github.com/lctt/lctt-cli)** - - How to analyze your system with perf and Python ====== diff --git a/sources/tech/20180806 GPaste Is A Great Clipboard Manager For Gnome Shell.md b/sources/tech/20180806 GPaste Is A Great Clipboard Manager For Gnome Shell.md deleted file mode 100644 index be86776740..0000000000 --- a/sources/tech/20180806 GPaste Is A Great Clipboard Manager For Gnome Shell.md +++ /dev/null @@ -1,98 +0,0 @@ -translating---geekpi - -GPaste Is A Great Clipboard Manager For Gnome Shell -====== -**[GPaste][1] is a clipboard management system that consists of a library, daemon, and interfaces for the command line and Gnome (using a native Gnome Shell extension).** - -A clipboard manager allows keeping track of what you're copying and pasting, providing access to previously copied items. GPaste, with its native Gnome Shell extension, makes the perfect addition for those looking for a Gnome clipboard manager. - -[![GPaste Gnome Shell extension Ubuntu 18.04][2]][3] -GPaste Gnome Shell extension -**Using GPaste in Gnome, you get a configurable, searchable clipboard history, available with a click on the top panel. GPaste remembers not only the text you copy, but also file paths and images** (the latter needs to be enabled from its settings as it's disabled by default). - -What's more, GPaste can detect growing lines, meaning it can detect when a new text copy is an extension of another and replaces it if it's true, useful for keeping your clipboard clean. - -From the extension menu you can pause GPaste from tracking the clipboard, and remove items from the clipboard history or the whole history. You'll also find a button that launches the GPaste user interface window. - -**If you prefer to use the keyboard, you can use a key shortcut to open the GPaste history from the top bar** (`Ctrl + Alt + H`), **or open the full GPaste GUI** (`Ctrl + Alt + G`). - -The tool also incorporates keyboard shortcuts to (can be changed): - - * delete the active item from history: `Ctrl + Alt + V` - - * **mark the active item as being a password (which obfuscates the clipboard entry in GPaste):** `Ctrl + Alt + S` - - * sync the clipboard to the primary selection: `Ctrl + Alt + O` - - * sync the primary selection to the clipboard: `Ctrl + Alt + P` - - * upload the active item to a pastebin service: `Ctrl + Alt + U` - -[![][4]][5] -GPaste GUI - -The GPaste interface window provides access to the clipboard history (with options to clear, edit or upload items), which can be searched, an option to pause GPaste from tracking the clipboard, restart the GPaste daemon, backup current clipboard history, as well as to its settings. - -[![][6]][7] -GPaste GUI - -From the GPaste UI you can change settings like: - - * Enable or disable the Gnome Shell extension - * Sync the daemon state with the extension's one - * Primary selection affects history - * Synchronize clipboard with primary selection - * Image support - * Trim items - * Detect growing lines - * Save history - * History settings like max history size, memory usage, max text item length, and more - * Keyboard shortcuts - - - -### Download GPaste - -[Download GPaste](https://github.com/Keruspe/GPaste) - -The Gpaste project page does not link to any GPaste binaries, and only source installation instructions. Users running Linux distributions other than Debian or Ubuntu (for which you'll find GPaste installation instructions below) can search their distro repositories for GPaste. - -Do not confuse GPaste with the GPaste Integration extension posted on the Gnome Shell extension website. That is a Gnome Shell extension that uses GPaste daemon, which is no longer maintained. The native Gnome Shell extension built into GPaste is still maintained. - -#### Install GPaste in Ubuntu (18.04, 16.04) or Debian (Jessie and newer) - -**For Debian, GPaste is available for Jessie and newer, while for Ubuntu, GPaste is in the repositories for 16.04 and newer (so it's available in the Ubuntu 18.04 Bionic Beaver).** - -**You can install GPaste (the daemon and the Gnome Shell extension) in Debian or Ubuntu using this command:** -``` -sudo apt install gnome-shell-extensions-gpaste gpaste - -``` - -After the installation completes, restart Gnome Shell by pressing `Alt + F2` and typing `r` , then pressing the `Enter` key. The GPaste Gnome Shell extension should now be enabled and its icon should show up on the top Gnome Shell panel. If it's not, use Gnome Tweaks (Gnome Tweak Tool) to enable the extension. - -**The GPaste 3.28.0 package from[Debian][8] and [Ubuntu][9] has a bug that makes it crash if the image support option is enabled, so do not enable this feature for now.** This was marked as - - --------------------------------------------------------------------------------- - -via: https://www.linuxuprising.com/2018/08/gpaste-is-great-clipboard-manager-for.html - -作者：[Logix][a] -选题：[lujun9972](https://github.com/lujun9972) -译者：[译者ID](https://github.com/译者ID) -校对：[校对者ID](https://github.com/校对者ID) - -本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 - -[a]:https://plus.google.com/118280394805678839070 -[1]:https://github.com/Keruspe/GPaste -[2]:https://2.bp.blogspot.com/-2ndArDBcrwY/W2gyhMc1kEI/AAAAAAAABS0/ZAe_onuGCacMblF733QGBX3XqyZd--WuACLcBGAs/s400/gpaste-gnome-shell-extension-ubuntu1804.png (Gpaste Gnome Shell) -[3]:https://2.bp.blogspot.com/-2ndArDBcrwY/W2gyhMc1kEI/AAAAAAAABS0/ZAe_onuGCacMblF733QGBX3XqyZd--WuACLcBGAs/s1600/gpaste-gnome-shell-extension-ubuntu1804.png -[4]:https://2.bp.blogspot.com/-7FBRsZJvYek/W2gyvzmeRxI/AAAAAAAABS4/LhokMFSn8_kZndrNB-BTP4W3e9IUuz9BgCLcBGAs/s640/gpaste-gui_1.png -[5]:https://2.bp.blogspot.com/-7FBRsZJvYek/W2gyvzmeRxI/AAAAAAAABS4/LhokMFSn8_kZndrNB-BTP4W3e9IUuz9BgCLcBGAs/s1600/gpaste-gui_1.png -[6]:https://4.bp.blogspot.com/-047ShYc6RrQ/W2gyz5FCf_I/AAAAAAAABTA/-o6jaWzwNpsSjG0QRwRJ5Xurq_A6dQ0sQCLcBGAs/s640/gpaste-gui_2.png -[7]:https://4.bp.blogspot.com/-047ShYc6RrQ/W2gyz5FCf_I/AAAAAAAABTA/-o6jaWzwNpsSjG0QRwRJ5Xurq_A6dQ0sQCLcBGAs/s1600/gpaste-gui_2.png -[8]:https://packages.debian.org/buster/gpaste -[9]:https://launchpad.net/ubuntu/+source/gpaste -[10]:https://www.imagination-land.org/posts/2018-04-13-gpaste-3.28.2-released.html diff --git a/sources/tech/20180814 HTTP request routing and validation with gorilla-mux.md b/sources/tech/20180814 HTTP request routing and validation with gorilla-mux.md index 410f692ad9..b1357ca9de 100644 --- a/sources/tech/20180814 HTTP request routing and validation with gorilla-mux.md +++ b/sources/tech/20180814 HTTP request routing and validation with gorilla-mux.md @@ -1,3 +1,5 @@ +yongshouzhang translating + HTTP request routing and validation with gorilla/mux ====== diff --git a/sources/tech/20180928 Quiet log noise with Python and machine learning.md b/sources/tech/20180928 Quiet log noise with Python and machine learning.md index 79894775ed..f1fe2f1b7f 100644 --- a/sources/tech/20180928 Quiet log noise with Python and machine learning.md +++ b/sources/tech/20180928 Quiet log noise with Python and machine learning.md @@ -1,5 +1,3 @@ -translating by Flowsnow - Quiet log noise with Python and machine learning ====== diff --git a/sources/tech/20181004 4 Must-Have Tools for Monitoring Linux.md b/sources/tech/20181004 4 Must-Have Tools for Monitoring Linux.md index 987809aa0d..beb3bab797 100644 --- a/sources/tech/20181004 4 Must-Have Tools for Monitoring Linux.md +++ b/sources/tech/20181004 4 Must-Have Tools for Monitoring Linux.md @@ -1,5 +1,3 @@ -### translating by way-ww - 4 Must-Have Tools for Monitoring Linux ====== diff --git a/sources/tech/20181008 Taking notes with Laverna, a web-based information organizer.md b/sources/tech/20181008 Taking notes with Laverna, a web-based information organizer.md index 71adf0112b..27616a9f6e 100644 --- a/sources/tech/20181008 Taking notes with Laverna, a web-based information organizer.md +++ b/sources/tech/20181008 Taking notes with Laverna, a web-based information organizer.md @@ -1,5 +1,3 @@ -translating by cyleft - Taking notes with Laverna, a web-based information organizer ====== diff --git a/sources/tech/20181011 Exploring the Linux kernel- The secrets of Kconfig-kbuild.md b/sources/tech/20181011 Exploring the Linux kernel- The secrets of Kconfig-kbuild.md index f2885b177c..2fd085eda0 100644 --- a/sources/tech/20181011 Exploring the Linux kernel- The secrets of Kconfig-kbuild.md +++ b/sources/tech/20181011 Exploring the Linux kernel- The secrets of Kconfig-kbuild.md @@ -1,4 +1,5 @@ -translating by leemeans +Translating by Jamskr + Exploring the Linux kernel: The secrets of Kconfig/kbuild ====== Dive into understanding how the Linux config/build system works. diff --git a/sources/tech/20181025 How to write your favorite R functions in Python.md b/sources/tech/20181025 How to write your favorite R functions in Python.md deleted file mode 100644 index a06d3557b9..0000000000 --- a/sources/tech/20181025 How to write your favorite R functions in Python.md +++ /dev/null @@ -1,153 +0,0 @@ -How to write your favorite R functions in Python -====== -R or Python? This Python script mimics convenient R-style functions for doing statistics nice and easy. - - - -One of the great modern battles of data science and machine learning is "Python vs. R." There is no doubt that both have gained enormous ground in recent years to become top programming languages for data science, predictive analytics, and machine learning. In fact, according to a recent IEEE article, Python overtook C++ as the [top programming language][1] and R firmly secured its spot in the top 10. - -However, there are some fundamental differences between these two. [R was developed primarily][2] as a tool for statistical analysis and quick prototyping of a data analysis problem. Python, on the other hand, was developed as a general purpose, modern object-oriented language in the same vein as C++ or Java but with a simpler learning curve and more flexible demeanor. Consequently, R continues to be extremely popular among statisticians, quantitative biologists, physicists, and economists, whereas Python has slowly emerged as the top language for day-to-day scripting, automation, backend web development, analytics, and general machine learning frameworks and has an extensive support base and open source development community work. - -### Mimicking functional programming in a Python environment - -[R's nature as a functional programming language][3] provides users with an extremely simple and compact interface for quick calculations of probabilities and essential descriptive/inferential statistics for a data analysis problem. For example, wouldn't it be great to be able to solve the following problems with just a single, compact function call? - - * How to calculate the mean/median/mode of a data vector. - * How to calculate the cumulative probability of some event following a normal distribution. What if the distribution is Poisson? - * How to calculate the inter-quartile range of a series of data points. - * How to generate a few random numbers following a Student's t-distribution. - - - -The R programming environment can do all of these. - -On the other hand, Python's scripting ability allows analysts to use those statistics in a wide variety of analytics pipelines with limitless sophistication and creativity. - -To combine the advantages of both worlds, you just need a simple Python-based wrapper library that contains the most commonly used functions pertaining to probability distributions and descriptive statistics defined in R-style. This enables you to call those functions really fast without having to go to the proper Python statistical libraries and figure out the whole list of methods and arguments. - -### Python wrapper script for most convenient R-functions - -[I wrote a Python script][4] to define the most convenient and widely used R-functions in simple, statistical analysis—in Python. After importing this script, you will be able to use those R-functions naturally, just like in an R programming environment. - -The goal of this script is to provide simple Python subroutines mimicking R-style statistical functions for quickly calculating density/point estimates, cumulative distributions, and quantiles and generating random variates for important probability distributions. - -To maintain the spirit of R styling, the script uses no class hierarchy and only raw functions are defined in the file. Therefore, a user can import this one Python script and use all the functions whenever they're needed with a single name call. - -Note that I use the word mimic. Under no circumstance am I claiming to emulate R's true functional programming paradigm, which consists of a deep environmental setup and complex relationships between those environments and objects. This script allows me (and I hope countless other Python users) to quickly fire up a Python program or Jupyter notebook, import the script, and start doing simple descriptive statistics in no time. That's the goal, nothing more, nothing less. - -If you've coded in R (maybe in grad school) and are just starting to learn and use Python for data analysis, you will be happy to see and use some of the same well-known functions in your Jupyter notebook in a manner similar to how you use them in your R environment. - -Whatever your reason, using this script is fun. - -### Simple examples - -To start, just import the script and start working with lists of numbers as if they were data vectors in R. - -``` -from R_functions import * -lst=[20,12,16,32,27,65,44,45,22,18] - -``` - -Say you want to calculate the [Tuckey five-number][5] summary from a vector of data points. You just call one simple function, **fivenum** , and pass on the vector. It will return the five-number summary in a NumPy array. - -``` -lst=[20,12,16,32,27,65,44,45,22,18] -fivenum(lst) -> array([12. , 18.5, 24.5, 41. , 65. ]) -``` - -Maybe you want to know the answer to the following question: - -Suppose a machine outputs 10 finished goods per hour on average with a standard deviation of 2. The output pattern follows a near normal distribution. What is the probability that the machine will output at least 7 but no more than 12 units in the next hour? - -The answer is essentially this: - - - -You can obtain the answer with just one line of code using **pnorm** : - -``` -pnorm(12,10,2)-pnorm(7,10,2) -> 0.7745375447996848 -``` - -Or maybe you need to answer the following: - -Suppose you have a loaded coin with the probability of turning heads up 60% every time you toss it. You are playing a game of 10 tosses. How do you plot and map out the chances of all the possible number of wins (from 0 to 10) with this coin? - -You can obtain a nice bar chart with just a few lines of code using just one function, **dbinom** : - -``` -probs=[] -import matplotlib.pyplot as plt -for i in range(11): - probs.append(dbinom(i,10,0.6)) -plt.bar(range(11),height=probs) -plt.grid(True) -plt.show() -``` - - - -### Simple interface for probability calculations - -R offers an extremely simple and intuitive interface for quick calculations from essential probability distributions. The interface goes like this: - - * **d** {distribution} gives the density function value at a point **x** - * **p** {distribution} gives the cumulative value at a point **x** - * **q** {distribution} gives the quantile function value at a probability **p** - * **r** {distribution} generates one or multiple random variates - - - -In our implementation, we stick to this interface and its associated argument list so you can execute these functions exactly like you would in an R environment. - -### Currently implemented functions - -The following R-style functions are implemented in the script for fast calling. - - * Mean, median, variance, standard deviation - * Tuckey five-number summary, IQR - * Covariance of a matrix or between two vectors - * Density, cumulative probability, quantile function, and random variate generation for the following distributions: normal, uniform, binomial, Poisson, F, Student's t, Chi-square, beta, and gamma. - - - -### Work in progress - -Obviously, this is a work in progress, and I plan to add some other convenient R-functions to this script. For example, in R, a single line of command **lm** can get you an ordinary least-square fitted model to a numerical dataset with all the necessary inferential statistics (P-values, standard error, etc.). This is powerfully brief and compact! On the other hand, standard linear regression problems in Python are often tackled using [Scikit-learn][6], which needs a bit more scripting for this use, so I plan to incorporate this single function linear model fitting feature using Python's [statsmodels][7] backend. - -If you like and use this script in your work, please help others find it by starring or forking its [GitHub repository][8]. Also, you can check my other [GitHub repos][9] for fun code snippets in Python, R, or MATLAB and some machine learning resources. - -If you have any questions or ideas to share, please contact me at [tirthajyoti[AT]gmail.com][10]. If you are, like me, passionate about machine learning and data science, please [add me on LinkedIn][11] or [follow me on Twitter. ][12] - -Originally published on [Towards Data Science][13]. Reposted under [CC BY-SA 4.0][14]. - --------------------------------------------------------------------------------- - -via: https://opensource.com/article/18/10/write-favorite-r-functions-python - -作者：[Tirthajyoti Sarkar][a] -选题：[lujun9972][b] -译者：[译者ID](https://github.com/译者ID) -校对：[校对者ID](https://github.com/校对者ID) - -本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 - -[a]: https://opensource.com/users/tirthajyoti -[b]: https://github.com/lujun9972 -[1]: https://spectrum.ieee.org/at-work/innovation/the-2018-top-programming-languages -[2]: https://www.coursera.org/lecture/r-programming/overview-and-history-of-r-pAbaE -[3]: http://adv-r.had.co.nz/Functional-programming.html -[4]: https://github.com/tirthajyoti/StatsUsingPython/blob/master/R_Functions.py -[5]: https://en.wikipedia.org/wiki/Five-number_summary -[6]: http://scikit-learn.org/stable/ -[7]: https://www.statsmodels.org/stable/index.html -[8]: https://github.com/tirthajyoti/StatsUsingPython -[9]: https://github.com/tirthajyoti?tab=repositories -[10]: mailto:tirthajyoti@gmail.com -[11]: https://www.linkedin.com/in/tirthajyoti-sarkar-2127aa7/ -[12]: https://twitter.com/tirthajyotiS -[13]: https://towardsdatascience.com/how-to-write-your-favorite-r-functions-in-python-11e1e9c29089 -[14]: https://creativecommons.org/licenses/by-sa/4.0/ diff --git a/sources/tech/20181105 5 Easy Tips for Linux Web Browser Security.md b/sources/tech/20181105 5 Easy Tips for Linux Web Browser Security.md deleted file mode 100644 index 17d06c72d6..0000000000 --- a/sources/tech/20181105 5 Easy Tips for Linux Web Browser Security.md +++ /dev/null @@ -1,157 +0,0 @@ -5 Easy Tips for Linux Web Browser Security -====== - - -If you use your Linux desktop and never open a web browser, you are a special kind of user. For most of us, however, a web browser has become one of the most-used digital tools on the planet. We work, we play, we get news, we interact, we bank… the number of things we do via a web browser far exceeds what we do in local applications. Because of that, we need to be cognizant of how we work with web browsers, and do so with a nod to security. Why? Because there will always be nefarious sites and people, attempting to steal information. Considering the sensitive nature of the information we send through our web browsers, it should be obvious why security is of utmost importance. - -So, what is a user to do? In this article, I’ll offer a few basic tips, for users of all sorts, to help decrease the chances that your data will end up in the hands of the wrong people. I will be demonstrating on the Firefox web browser, but many of these tips cross the application threshold and can be applied to any flavor of web browser. - -### 1. Choose Your Browser Wisely - -Although most of these tips apply to most browsers, it is imperative that you select your web browser wisely. One of the more important aspects of browser security is the frequency of updates. New issues are discovered quite frequently and you need to have a web browser that is as up to date as possible. Of major browsers, here is how they rank with updates released in 2017: - - 1. Chrome released 8 updates (with Chromium following up with numerous security patches throughout the year). - - 2. Firefox released 7 updates. - - 3. Edge released 2 updates. - - 4. Safari released 1 update (although Apple does release 5-6 security patches yearly). - - - - -But even if your browser of choice releases an update every month, if you (as a user) don’t upgrade, that update does you no good. This can be problematic with certain Linux distributions. Although many of the more popular flavors of Linux do a good job of keeping web browsers up to date, others do not. So, it’s crucial that you manually keep on top of browser updates. This might mean your distribution of choice doesn’t include the latest version of your web browser of choice in its standard repository. If that’s the case, you can always manually download the latest version of the browser from the developer’s download page and install from there. - -If you like to live on the edge, you can always use a beta or daily build version of your browser. Do note, that using a daily build or beta version does come with it the possibility of unstable software. Say, however, you’re okay with using a daily build of Firefox on a Ubuntu-based distribution. To do that, add the necessary repository with the command: - -``` -sudo apt-add-repository ppa:ubuntu-mozilla-daily/ppa -``` - -Update apt and install the daily Firefox with the commands: - -``` -sudo apt-get update -sudo apt-get install firefox -``` - -What’s most important here is to never allow your browser to get far out of date. You want to have the most updated version possible on your desktop. Period. If you fail this one thing, you could be using a browser that is vulnerable to numerous issues. - -### 2. Use A Private Window - -Now that you have your browser updated, how do you best make use of it? If you happen to be of the really concerned type, you should consider always using a private window. Why? Private browser windows don’t retain your data: No passwords, no cookies, no cache, no history… nothing. The one caveat to browsing through a private window is that (as you probably expect), every time you go back to a web site, or use a service, you’ll have to re-type any credentials to log in. If you’re serious about browser security, never saving credentials should be your default behavior. - -This leads me to a reminder that everyone needs: Make your passwords strong! In fact, at this point in the game, everyone should be using a password manager to store very strong passwords. My password manager of choice is [Universal Password Manager][1]. - -### 3\. Protect Your Passwords - -For some, having to retype those passwords every single time might be too much. So what do you do if you want to protect those passwords, while not having to type them constantly? If you use Firefox, there’s a built-in tool, called Master Password. With this enabled, none of your browser’s saved passwords are accessible, until you correctly type the master password. To set this up, do the following: - - 1. Open Firefox. - - 2. Click the menu button. - - 3. Click Preferences. - - 4. In the Preferences window, click Privacy & Security. - - 5. In the resulting window, click the checkbox for Use a master password (Figure 1). - - 6. When prompted, type and verify your new master password (Figure 2). - - 7. Close and reopen Firefox. - - - - -![Master Password][3] - -Figure 1: The Master Password option in Firefox Preferences. - -[Used with permission][4] - -![Setting password][6] - -Figure 2: Setting the Master Password in Firefox. - -[Used with permission][4] - -### 4\. Know your Extensions - -There are plenty of privacy-focused extensions available for most browsers. What extensions you use will depend upon what you want to focus on. For myself, I choose the following extensions for Firefox: - - * [Firefox Multi-Account Containers][7] \- Allows you to configure certain sites to open in a containerized tab. - - * [Facebook Container][8] \- Always opens Facebook in a containerized tab (Firefox Multi-Account Containers is required for this). - - * [Avast Online Security][9] \- Identifies and blocks known phishing sites and displays a website’s security rating (curated by the Avast community of over 400 million users). - - * [Mining Blocker][10] \- Blocks all CPU-Crypto Miners before they are loaded. - - * [PassFF][11] \- Integrates with pass (A UNIX password manager) to store credentials safely. - - * [Privacy Badger][12] \- Automatically learns to block trackers. - - * [uBlock Origin][13] \- Blocks trackers based on known lists. - - -Of course, you’ll find plenty more security-focused extensions for: - - - -+ [Firefox][2] - -+ [Chrome, Chromium, & Vivaldi][5] - -+ [Opera][14] - - -Not every web browser offers extensions. Some, such as Midoria, offer a limited about of built-in plugins, that can be enabled/disabled (Figure 3). However, you won’t find third-party plugins available for the majority of these lightweight browsers. - -![Midori Browser][15] - -Figure 3: The Midori Browser plugins window. - -[Used with permission][4] - -### 5\. Virtualize - -For those that are concerned about releasing locally stored data to prying eyes, one option would be to only use a browser on a virtual machine. To do this, install the likes of [VirtualBox][16], install a Linux guest, and then run whatever browser you like in the virtual environment. If you then apply the above tips, you can be sure your browsing experience will be safe. - -### The Truth of the Matter - -The truth is, if the machine you are working from is on a network, you’re never going to be 100% safe. However, if you use that web browser intelligently you’ll get more bang out of your security buck and be less prone to having data stolen. The silver lining with Linux is that the chances of getting malicious software installed on your machine is exponentially less than if you were using another platform. Just remember to always use the latest release of your browser, keep your operating system updated, and use caution with the sites you visit. - -Learn more about Linux through the free ["Introduction to Linux" ][17] course from The Linux Foundation and edX. - --------------------------------------------------------------------------------- - -via: https://www.linux.com/learn/intro-to-linux/2018/11/5-easy-tips-linux-web-browser-security - -作者：[Jack Wallen][a] -选题：[lujun9972][b] -译者：[译者ID](https://github.com/译者ID) -校对：[校对者ID](https://github.com/校对者ID) - -本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 - -[a]: https://www.linux.com/users/jlwallen -[b]: https://github.com/lujun9972 -[1]: http://upm.sourceforge.net/ -[2]: https://addons.mozilla.org/en-US/firefox/search/?q=security -[3]: https://www.linux.com/sites/lcom/files/styles/rendered_file/public/browsersecurity_1.jpg?itok=gHMPKEvr (Master Password) -[4]: https://www.linux.com/licenses/category/used-permission -[5]: https://chrome.google.com/webstore/search/security -[6]: https://www.linux.com/sites/lcom/files/styles/rendered_file/public/browsersecurity_2.jpg?itok=4L7DR2Ik (Setting password) -[7]: https://addons.mozilla.org/en-US/firefox/addon/multi-account-containers/?src=search -[8]: https://addons.mozilla.org/en-US/firefox/addon/facebook-container/?src=search -[9]: https://addons.mozilla.org/en-US/firefox/addon/avast-online-security/?src=search -[10]: https://addons.mozilla.org/en-US/firefox/addon/miningblocker/?src=search -[11]: https://addons.mozilla.org/en-US/firefox/addon/passff/?src=search -[12]: https://addons.mozilla.org/en-US/firefox/addon/privacy-badger17/ -[13]: https://addons.mozilla.org/en-US/firefox/addon/ublock-origin/?src=search -[14]: https://addons.opera.com/en/search/?query=security -[15]: https://www.linux.com/sites/lcom/files/styles/rendered_file/public/browsersecurity_3.jpg?itok=hdNor0gw (Midori Browser) -[16]: https://www.virtualbox.org/ -[17]: https://training.linuxfoundation.org/linux-courses/system-administration-training/introduction-to-linux diff --git a/sources/tech/20181105 5 Minimal Web Browsers for Linux.md b/sources/tech/20181105 5 Minimal Web Browsers for Linux.md new file mode 100644 index 0000000000..1fbc18aeae --- /dev/null +++ b/sources/tech/20181105 5 Minimal Web Browsers for Linux.md @@ -0,0 +1,163 @@ +[#]: collector: (lujun9972) +[#]: translator: ( ) +[#]: reviewer: ( ) +[#]: publisher: ( ) +[#]: subject: (5 Minimal Web Browsers for Linux) +[#]: via: (https://www.linux.com/blog/intro-to-linux/2018/11/5-minimal-web-browsers-linux) +[#]: author: (Jack Wallen https://www.linux.com/users/jlwallen) +[#]: url: ( ) + +5 Minimal Web Browsers for Linux +====== + + +There are so many reasons to enjoy the Linux desktop. One reason I often state up front is the almost unlimited number of choices to be found at almost every conceivable level. From how you interact with the operating system (via a desktop interface), to how daemons run, to what tools you use, you have a multitude of options. + +The same thing goes for web browsers. You can use anything from open source favorites, such as [Firefox][1] and [Chromium][2], or closed sourced industry darlings like [Vivaldi][3] and [Chrome][4]. Those options are full-fledged browsers with every possible bell and whistle you’ll ever need. For some, these feature-rich browsers are perfect for everyday needs. + +There are those, however, who prefer using a web browser without all the frills. In fact, there are many reasons why you might prefer a minimal browser over a standard browser. For some, it’s about browser security, while others look at a web browser as a single-function tool (as opposed to a one-stop shop application). Still others might be running low-powered machines that cannot handle the requirements of, say, Firefox or Chrome. Regardless of the reason, Linux has you covered. + +Let’s take a look at five of the minimal browsers that can be installed on Linux. I’ll be demonstrating these browsers on the Elementary OS platform, but each of these browsers are available to nearly every distribution in the known Linuxverse. Let’s dive in. + +### GNOME Web + +GNOME Web (codename Epiphany, which means [“a usually sudden manifestation or perception of the essential nature or meaning of something”][5]) is the default web browser for Elementary OS, but it can be installed from the standard repositories. (Note, however, that the recommended installation of Epiphany is via Flatpak or Snap). If you choose to install via the standard package manager, issue a command such as sudo apt-get install epiphany-browser -y for successful installation. + +Epiphany uses the WebKit rendering engine, which is the same engine used in Apple’s Safari browser. Couple that rendering engine with the fact that Epiphany has very little in terms of bloat to get in the way, you will enjoy very fast page-rendering speeds. Epiphany development follows strict adherence to the following guidelines: + + * Simplicity - Feature bloat and user interface clutter are considered evil. + + * Standards compliance - No non-standard features will ever be introduced to the codebase. + + * Software freedom - Epiphany will always be released under a license that respects freedom. + + * Human interface - Epiphany follows the [GNOME Human Interface Guidelines][6]. + + * Minimal preferences - Preferences are only added when they make sense and after careful consideration. + + * Target audience - Non-technical users are the primary target audience (which helps to define the types of features that are included). + + + + +GNOME Web is as clean and simple a web browser as you’ll find (Figure 1). + +![GNOME Web][8] + +Figure 1: The GNOME Web browser displaying a minimal amount of preferences for the user. + +[Used with permission][9] + +The GNOME Web manifesto reads: + +A web browser is more than an application: it is a way of thinking, a way of seeing the world. Epiphany's principles are simplicity, standards compliance, and software freedom. + +### Netsurf + +The [Netsurf][10] minimal web browser opens almost faster than you can release the mouse button. Netsurf uses its own layout and rendering engine (designed completely from scratch), which is rather hit and miss in its rendering (Figure 2). + + + +Although you might find Netsurf to suffer from rendering issues on certain sites, understand the Hubbub HTML parser is following the work-in-progress HTML5 specification, so there will be issues popup now and then. To ease those rendering headaches, Netsurf does include HTTPS support, web page thumbnailing, URL completion, scale view, bookmarks, full-screen mode, keyboard shorts, and no particular GUI toolkit requirements. That last bit is important, especially when you switch from one desktop to another. + +For those curious as to the requirements for Netsurf, the browser can run on a machine as slow as a 30Mhz ARM 6 computer with 16MB of RAM. That’s impressive, by today’s standard. + +### QupZilla + +If you’re looking for a minimal browser that uses the Qt Framework and the QtWebKit rendering engine, [QupZilla][11] might be exactly what you’re looking for. QupZilla does include all the standard features and functions you’d expect from a web browser, such as bookmarks, history, sidebar, tabs, RSS feeds, ad blocking, flash blocking, and CA Certificates management. Even with those features, QupZilla still manages to remain a very fast lightweight web browser. Other features include: Fast startup, speed dial homepage, built-in screenshot tool, browser themes, and more. +One feature that should appeal to average users is that QupZilla has a more standard preferences tools than found in many lightweight browsers (Figure 3). So, if going too far outside the lines isn’t your style, but you still want something lighter weight, QupZilla is the browser for you. + +![QupZilla][13] + +Figure 3: The QupZilla preferences tool. + +[Used with permission][9] + +### Otter Browser + +Otter Browser is a free, open source attempt to recreate the closed-source offerings found in the Opera Browser. Otter Browser uses the WebKit rendering engine and has an interface that should be immediately familiar with any user. Although lightweight, Otter Browser does include full-blown features such as: + + * Passwords manager + + * Add-on manager + + * Content blocking + + * Spell checking + + * Customizable GUI + + * URL completion + + * Speed dial (Figure 4) + + * Bookmarks and various related features + + * Mouse gestures + + * User style sheets + + * Built-in Note tool + + +![Otter][15] + +Figure 4: The Otter Browser Speed Dial tab. + +[Used with permission][9] + +Otter Browser can be run on nearly any Linux distribution from an [AppImage][16], so there’s no installation required. Just download the AppImage file, give the file executable permissions (with the command chmod u+x otter-browser-*.AppImage), and then launch the app with the command ./otter-browser*.AppImage. + +Otter Browser does an outstanding job of rendering websites and could function as your go-to minimal browser with ease. + +### Lynx + +Let’s get really minimal. When I first started using Linux, back in ‘97, one of the web browsers I often turned to was a text-only take on the app called [Lynx][17]. It should come as no surprise that Lynx is still around and available for installation from the standard repositories. As you might expect, Lynx works from the terminal window and doesn’t display pretty pictures or render much in the way of advanced features (Figure 5). In fact, Lynx is as bare-bones a browser as you will find available. Because of how bare-bones this web browser is, it’s not recommended for everyone. But if you happen to have a gui-less web server and you have a need to be able to read the occasional website, Lynx can be a real lifesaver. + +![Lynx][19] + +Figure 5: The Lynx browser rendering the Linux.com page. + +[Used with permission][9] + +I have also found Lynx an invaluable tool when troubleshooting certain aspects of a website (or if some feature on a website is preventing me from viewing the content in a regular browser). Another good reason to use Lynx is when you only want to view the content (and not the extraneous elements). + +### Plenty More Where This Came From + +There are plenty more minimal browsers than this. But the list presented here should get you started down the path of minimalism. One (or more) of these browsers are sure to fill that need, whether you’re running it on a low-powered machine or not. + +Learn more about Linux through the free ["Introduction to Linux" ][20]course from The Linux Foundation and edX. + +-------------------------------------------------------------------------------- + +via: https://www.linux.com/blog/intro-to-linux/2018/11/5-minimal-web-browsers-linux + +作者：[Jack Wallen][a] +选题：[lujun9972][b] +译者：[译者ID](https://github.com/译者ID) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]: https://www.linux.com/users/jlwallen +[b]: https://github.com/lujun9972 +[1]: https://www.mozilla.org/en-US/firefox/new/ +[2]: https://www.chromium.org/ +[3]: https://vivaldi.com/ +[4]: https://www.google.com/chrome/ +[5]: https://www.merriam-webster.com/dictionary/epiphany +[6]: https://developer.gnome.org/hig/stable/ +[7]: /files/images/minimalbrowsers1jpg +[8]: https://www.linux.com/sites/lcom/files/styles/rendered_file/public/minimalbrowsers_1.jpg?itok=Q7wZLF8B (GNOME Web) +[9]: /licenses/category/used-permission +[10]: https://www.netsurf-browser.org/ +[11]: https://qupzilla.com/ +[12]: /files/images/minimalbrowsers3jpg +[13]: https://www.linux.com/sites/lcom/files/styles/rendered_file/public/minimalbrowsers_3.jpg?itok=O8iMALWO (QupZilla) +[14]: /files/images/minimalbrowsers4jpg +[15]: https://www.linux.com/sites/lcom/files/styles/rendered_file/public/minimalbrowsers_4.jpg?itok=5bCa0z-e (Otter) +[16]: https://sourceforge.net/projects/otter-browser/files/ +[17]: https://lynx.browser.org/ +[18]: /files/images/minimalbrowsers5jpg +[19]: https://www.linux.com/sites/lcom/files/styles/rendered_file/public/minimalbrowsers_5.jpg?itok=p_Lmiuxh (Lynx) +[20]: https://training.linuxfoundation.org/linux-courses/system-administration-training/introduction-to-linux diff --git a/sources/tech/20181107 Top 30 OpenStack Interview Questions and Answers.md b/sources/tech/20181107 Top 30 OpenStack Interview Questions and Answers.md index e00fc5452b..dc5411f1fa 100644 --- a/sources/tech/20181107 Top 30 OpenStack Interview Questions and Answers.md +++ b/sources/tech/20181107 Top 30 OpenStack Interview Questions and Answers.md @@ -1,3 +1,6 @@ +ScarboroughCoral translating! + + Top 30 OpenStack Interview Questions and Answers ====== Now a days most of the firms are trying to migrate their IT infrastructure and Telco Infra into private cloud i.e OpenStack. If you planning to give interviews on Openstack admin profile, then below list of interview questions might help you to crack the interview. diff --git a/sources/tech/20181119 7 command-line tools for writers - Opensource.com.md b/sources/tech/20181119 7 command-line tools for writers - Opensource.com.md index a482895af2..a222389079 100644 --- a/sources/tech/20181119 7 command-line tools for writers - Opensource.com.md +++ b/sources/tech/20181119 7 command-line tools for writers - Opensource.com.md @@ -1,3 +1,5 @@ +Translating by LazyWolfLin + 7 command-line tools for writers | Opensource.com ====== Put away your word processor and start writing from the command line using these open source tools. diff --git a/sources/tech/20181119 9 obscure Python libraries for data science.md b/sources/tech/20181119 9 obscure Python libraries for data science.md deleted file mode 100644 index 0250199d7c..0000000000 --- a/sources/tech/20181119 9 obscure Python libraries for data science.md +++ /dev/null @@ -1,258 +0,0 @@ -heguangzhi Translating - -9 obscure Python libraries for data science -====== -Go beyond pandas, scikit-learn, and matplotlib and learn some new tricks for doing data science in Python. - -Python is an amazing language. In fact, it's one of the fastest growing programming languages in the world. It has time and again proved its usefulness both in developer job roles and data science positions across industries. The entire ecosystem of Python and its libraries makes it an apt choice for users (beginners and advanced) all over the world. One of the reasons for its success and popularity is its set of robust libraries that make it so dynamic and fast. - -In this article, we will look at some of the Python libraries for data science tasks other than the commonly used ones like **pandas, scikit-learn** , and **matplotlib**. Although libraries like **pandas and scikit-learn** are the ones that come to mind for machine learning tasks, it's always good to learn about other Python offerings in this field. - -### Wget - -Extracting data, especially from the web, is one of a data scientist's vital tasks. [Wget][1] is a free utility for non-interactive downloading files from the web. It supports HTTP, HTTPS, and FTP protocols, as well as retrieval through HTTP proxies. Since it is non-interactive, it can work in the background even if the user isn't logged in. So the next time you want to download a website or all the images from a page, **wget** will be there to assist. - -#### Installation - -``` -$ pip install wget -``` - -#### Example - -``` -import wget -url = 'http://www.futurecrew.com/skaven/song_files/mp3/razorback.mp3' - -filename = wget.download(url) -100% [................................................] 3841532 / 3841532 - -filename -'razorback.mp3' -``` - -### Pendulum - -For people who get frustrated when working with date-times in Python, **[Pendulum][2]** is here. It is a Python package to ease **datetime** manipulations. It is a drop-in replacement for Python's native class. Refer to the [documentation][3] for in-depth information. - -#### Installation - -``` -$ pip install pendulum -``` - -#### Example - -``` -import pendulum - -dt_toronto = pendulum.datetime(2012, 1, 1, tz='America/Toronto') -dt_vancouver = pendulum.datetime(2012, 1, 1, tz='America/Vancouver') - -print(dt_vancouver.diff(dt_toronto).in_hours()) - -3 -``` - -### Imbalanced-learn - -Most classification algorithms work best when the number of samples in each class is almost the same (i.e., balanced). But real-life cases are full of imbalanced datasets, which can have a bearing upon the learning phase and the subsequent prediction of machine learning algorithms. Fortunately, the **[imbalanced-learn][4]** library was created to address this issue. It is compatible with [**scikit-learn**][5] and is part of **[scikit-learn-contrib][6]** projects. Try it the next time you encounter imbalanced datasets. - -#### Installation - -``` -pip install -U imbalanced-learn - -# or - -conda install -c conda-forge imbalanced-learn -``` - -#### Example - -For usage and examples refer to the [documentation][7]. - -### FlashText - -Cleaning text data during natural language processing (NLP) tasks often requires replacing keywords in or extracting keywords from sentences. Usually, such operations can be accomplished with regular expressions, but they can become cumbersome if the number of terms to be searched runs into the thousands. - -Python's **[FlashText][8]** module, which is based upon the [FlashText algorithm][9], provides an apt alternative for such situations. The best part of FlashText is the runtime is the same irrespective of the number of search terms. You can read more about it in the [documentation][10]. - -#### Installation - -``` -$ pip install flashtext -``` - -#### Examples - -##### **Extract keywords:** - -``` -from flashtext import KeywordProcessor -keyword_processor = KeywordProcessor() - -# keyword_processor.add_keyword( , ) - -keyword_processor.add_keyword('Big Apple', 'New York') -keyword_processor.add_keyword('Bay Area') -keywords_found = keyword_processor.extract_keywords('I love Big Apple and Bay Area.') - -keywords_found -['New York', 'Bay Area'] -``` - -**Replace keywords:** - -``` -keyword_processor.add_keyword('New Delhi', 'NCR region') - -new_sentence = keyword_processor.replace_keywords('I love Big Apple and new delhi.') - -new_sentence -'I love New York and NCR region.' -``` - -For more examples, refer to the [usage][11] section in the documentation. - -### FuzzyWuzzy - -The name sounds weird, but **[FuzzyWuzzy][12]** is a very helpful library when it comes to string matching. It can easily implement operations like string comparison ratios, token ratios, etc. It is also handy for matching records kept in different databases. - -#### Installation - -``` -$ pip install fuzzywuzzy -``` - -#### Example - -``` -from fuzzywuzzy import fuzz -from fuzzywuzzy import process - -# Simple Ratio - -fuzz.ratio("this is a test", "this is a test!") -97 - -# Partial Ratio -fuzz.partial_ratio("this is a test", "this is a test!") - 100 -``` - -More examples can be found in FuzzyWuzzy's [GitHub repo.][12] - -### PyFlux - -Time-series analysis is one of the most frequently encountered problems in machine learning. **[PyFlux][13]** is an open source library in Python that was explicitly built for working with time-series problems. The library has an excellent array of modern time-series models, including but not limited to **ARIMA** , **GARCH** , and **VAR** models. In short, PyFlux offers a probabilistic approach to time-series modeling. It's worth trying out. - -#### Installation - -``` -pip install pyflux -``` - -#### Example - -Please refer to the [documentation][14] for usage and examples. - -### IPyvolume - -Communicating results is an essential aspect of data science, and visualizing results offers a significant advantage. **[**IPyvolume**][15]** is a Python library to visualize 3D volumes and glyphs (e.g., 3D scatter plots) in the Jupyter notebook with minimal configuration and effort. However, it is currently in the pre-1.0 stage. A good analogy would be something like this: IPyvolume's **volshow** is to 3D arrays what matplotlib's **imshow** is to 2D arrays. You can read more about it in the [documentation][16]. - -#### Installation - -``` -Using pip -$ pip install ipyvolume - -Conda/Anaconda -$ conda install -c conda-forge ipyvolume -``` - -#### Examples - -**Animation:** - - -**Volume rendering:** - - -### Dash - -**[Dash][17]** is a productive Python framework for building web applications. It is written on top of Flask, Plotly.js, and React.js and ties modern UI elements like drop-downs, sliders, and graphs to your analytical Python code without the need for JavaScript. Dash is highly suitable for building data visualization apps that can be rendered in the web browser. Consult the [user guide][18] for more details. - -#### Installation - -``` -pip install dash==0.29.0 # The core dash backend -pip install dash-html-components==0.13.2 # HTML components -pip install dash-core-components==0.36.0 # Supercharged components -pip install dash-table==3.1.3 # Interactive DataTable component (new!) -``` - -#### Example - -The following example shows a highly interactive graph with drop-down capabilities. As the user selects a value in the drop-down, the application code dynamically exports data from Google Finance into a Pandas DataFrame. - - -### Gym - -**[Gym][19]** from [OpenAI][20] is a toolkit for developing and comparing reinforcement learning algorithms. It is compatible with any numerical computation library, such as TensorFlow or Theano. The Gym library is a collection of test problems, also called environments, that you can use to work out your reinforcement-learning algorithms. These environments have a shared interface, which allows you to write general algorithms. - -#### Installation - -``` -pip install gym -``` - -#### Example - -The following example will run an instance of the environment **[CartPole-v0][21]** for 1,000 timesteps, rendering the environment at each step. - - -You can read about [other environments][22] on the Gym website. - -### Conclusion - -These are my picks for useful, but little-known Python libraries for data science. If you know another one to add to this list, please mention it in the comments below. - -This was originally published on the [Analytics Vidhya][23] Medium channel and is reprinted with permission. - --------------------------------------------------------------------------------- - -via: https://opensource.com/article/18/11/python-libraries-data-science - -作者：[Parul Pandey][a] -选题：[lujun9972][b] -译者：[译者ID](https://github.com/译者ID) -校对：[校对者ID](https://github.com/校对者ID) - -本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 - -[a]: https://opensource.com/users/parul-pandey -[b]: https://github.com/lujun9972 -[1]: https://pypi.org/project/wget/ -[2]: https://github.com/sdispater/pendulum -[3]: https://pendulum.eustace.io/docs/#installation -[4]: https://github.com/scikit-learn-contrib/imbalanced-learn -[5]: http://scikit-learn.org/stable/ -[6]: https://github.com/scikit-learn-contrib -[7]: http://imbalanced-learn.org/en/stable/api.html -[8]: https://github.com/vi3k6i5/flashtext -[9]: https://arxiv.org/abs/1711.00046 -[10]: https://flashtext.readthedocs.io/en/latest/ -[11]: https://flashtext.readthedocs.io/en/latest/#usage -[12]: https://github.com/seatgeek/fuzzywuzzy -[13]: https://github.com/RJT1990/pyflux -[14]: https://pyflux.readthedocs.io/en/latest/index.html -[15]: https://github.com/maartenbreddels/ipyvolume -[16]: https://ipyvolume.readthedocs.io/en/latest/?badge=latest -[17]: https://github.com/plotly/dash -[18]: https://dash.plot.ly/ -[19]: https://github.com/openai/gym -[20]: https://openai.com/ -[21]: https://gym.openai.com/envs/CartPole-v0 -[22]: https://gym.openai.com/ -[23]: https://medium.com/analytics-vidhya/python-libraries-for-data-science-other-than-pandas-and-numpy-95da30568fad diff --git a/sources/tech/20181119 Arch-Wiki-Man - A Tool to Browse The Arch Wiki Pages As Linux Man Page from Offline.md b/sources/tech/20181119 Arch-Wiki-Man - A Tool to Browse The Arch Wiki Pages As Linux Man Page from Offline.md new file mode 100644 index 0000000000..9e1ee18be7 --- /dev/null +++ b/sources/tech/20181119 Arch-Wiki-Man - A Tool to Browse The Arch Wiki Pages As Linux Man Page from Offline.md @@ -0,0 +1,214 @@ +[#]: collector: (lujun9972) +[#]: translator: ( ) +[#]: reviewer: ( ) +[#]: publisher: ( ) +[#]: subject: (Arch-Wiki-Man – A Tool to Browse The Arch Wiki Pages As Linux Man Page from Offline) +[#]: via: (https://www.2daygeek.com/arch-wiki-man-a-tool-to-browse-the-arch-wiki-pages-as-linux-man-page-from-offline/) +[#]: author: ([Prakash Subramanian](https://www.2daygeek.com/author/prakash/)) +[#]: url: ( ) + +Arch-Wiki-Man – A Tool to Browse The Arch Wiki Pages As Linux Man Page from Offline +====== + +Getting internet is not a big deal now a days, however there will be a limitation on technology. + +I was really surprise to see the technology growth but in the same time there will be fall in everywhere. + +Whenever you search anything about other Linux distributions most of the time you will get a third party links in the first place but for Arch Linux every time you would get the Arch Wiki page for your results. + +As Arch Wiki has most of the solution other than third party websites. + +As of now, you might used web browser to get a solution for your Arch Linux system but you no need to do the same for now. + +There is a solution is available in command line to perform this action much faster way and the utility called arch-wiki-man. If you are Arch Linux lover, i would suggest you to read **[Arch Linux Post Installation guide][1]** which helps you to tweak your system for day to day use. + +### What is arch-wiki-man? + +[arch-wiki-man][2] tool allows user to search the arch wiki pages right from the command line (CLI) instantly without internet connection. It allows user to access and search an entire wiki pages as a Linux man page. + +Also, you no need to switch to GUI. Updates are pushed automatically every two days so, your local copy of the Arch Wiki pages will be upto date. The tool name is `awman`. awman stands for Arch Wiki Man. + +We had already wrote similar kind of topic called **[Arch Wiki Command Line Utility][3]** (arch-wiki-cli) which allows user search Arch Wiki from command line but make sure you should have internet to use this utility. + +### How to Install arch-wiki-man tool? + +arch-wiki-man utility is available in AUR repository so, we need to use AUR helper to install it. There are many AUR helper is available and we had wrote an article about **[Yaourt AUR helper][4]** and **[Packer AUR helper][5]** which are very famous AUR helper. + +``` +$ yaourt -S arch-wiki-man + +or + +$ packer -S arch-wiki-man +``` + +Alternatively we can install it using npm package manager. Make sure, you should have installed **[NodeJS][6]** on your system. If so, run the following command to install it. + +``` +$ npm install -g arch-wiki-man +``` + +### How to Update the local Arch Wiki copy? + +As updated previously, updates are pushed automatically every two days and it can be done by running the following command. + +``` +$ sudo awman-update +[sudo] password for daygeek: +[email protected] /usr/lib/node_modules/arch-wiki-man +└── [email protected] + +arch-wiki-md-repo has been successfully updated or reinstalled. +``` + +awman-update is faster and more convenient method to get the update. However, you can get the updates by reinstalling this package using the following command. + +``` +$ yaourt -S arch-wiki-man + +or + +$ packer -S arch-wiki-man +``` + +### How to Use Arch Wiki from command line? + +It’s very simple interface and easy to use. To search anything, just run `awman` followed by the search term. The general syntax is as follow. + +``` +$ awman Search-Term +``` + +### How to Search Multiple Matches? + +If you would like to list all the results titles comes with `installation` string, run the following command format. If the output comes with multiple results then you will get a selection menu to navigate each item. + +``` +$ awman installation +``` + +![][8] + +Detailed page screenshot. +![][9] + +### Search a given string in Titles & Descriptions + +The `-d` or `--desc-search` option allow users to search a given string in titles and descriptions. + +``` +$ awman -d mirrors + +or + +$ awman --desc-search mirrors +? Select an article: (Use arrow keys) +❯ [1/3] Mirrors: Related articles + [2/3] DeveloperWiki-NewMirrors: Contents + [3/3] Powerpill: Powerpill is a pac +``` + +### Search a given string in Contents + +The `-k` or `--apropos` option allow users to search a given string in content as well. Make a note, this option significantly slower your search as this scan entire wiki page content. + +``` +$ awman -k openjdk + +or + +$ awman --apropos openjdk +? Select an article: (Use arrow keys) +❯ [1/26] Hadoop: Related articles + [2/26] XDG Base Directory support: Related articles + [3/26] Steam-Game-specific troubleshooting: See Steam/Troubleshooting first. + [4/26] Android: Related articles + [5/26] Elasticsearch: Elasticsearch is a search engine based on Lucene. It provides a distributed, mul.. + [6/26] LibreOffice: Related articles + [7/26] Browser plugins: Related articles +(Move up and down to reveal more choices) +``` + +### Open the search results in a web browser + +The `-w` or `--web` option allow users to open the search results in a web browser. + +``` +$ awman -w AUR helper + +or + +$ awman --web AUR helper +``` + +![][10] + +### Search in other languages + +The `-w` or `--web` option allow users to open the search results in a web browser. To see a list of supported language, run the following command. + +``` +$ awman --list-languages +arabic +bulgarian +catalan +chinesesim +chinesetrad +croatian +czech +danish +dutch +english +esperanto +finnish +greek +hebrew +hungarian +indonesian +italian +korean +lithuanian +norwegian +polish +portuguese +russian +serbian +slovak +spanish +swedish +thai +ukrainian +``` + +Run the awman command with your preferred language to see the results with different language other than English. + +``` +$ awman -l chinesesim deepin +``` + +![][11] + +-------------------------------------------------------------------------------- + +via: https://www.2daygeek.com/arch-wiki-man-a-tool-to-browse-the-arch-wiki-pages-as-linux-man-page-from-offline/ + +作者：[Prakash Subramanian][a] +选题：[lujun9972][b] +译者：[译者ID](https://github.com/译者ID) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]: https://www.2daygeek.com/author/prakash/ +[b]: https://github.com/lujun9972 +[1]: https://www.2daygeek.com/arch-linux-post-installation-30-things-to-do-after-installing-arch-linux/ +[2]: https://github.com/greg-js/arch-wiki-man +[3]: https://www.2daygeek.com/search-arch-wiki-website-command-line-terminal/ +[4]: https://www.2daygeek.com/install-yaourt-aur-helper-on-arch-linux/ +[5]: https://www.2daygeek.com/install-packer-aur-helper-on-arch-linux/ +[6]: https://www.2daygeek.com/install-nodejs-on-ubuntu-centos-debian-fedora-mint-rhel-opensuse/ +[7]: data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7 +[8]: https://www.2daygeek.com/wp-content/uploads/2018/11/arch-wiki-man-%E2%80%93-A-Tool-to-Browse-The-Arch-Wiki-Pages-As-Linux-Man-page-from-Offline-1.png +[9]: https://www.2daygeek.com/wp-content/uploads/2018/11/arch-wiki-man-%E2%80%93-A-Tool-to-Browse-The-Arch-Wiki-Pages-As-Linux-Man-page-from-Offline-2.png +[10]: https://www.2daygeek.com/wp-content/uploads/2018/11/arch-wiki-man-%E2%80%93-A-Tool-to-Browse-The-Arch-Wiki-Pages-As-Linux-Man-page-from-Offline-3.png +[11]: https://www.2daygeek.com/wp-content/uploads/2018/11/arch-wiki-man-%E2%80%93-A-Tool-to-Browse-The-Arch-Wiki-Pages-As-Linux-Man-page-from-Offline-4.png diff --git a/sources/tech/20181119 How To Customize Bash Prompt In Linux.md b/sources/tech/20181119 How To Customize Bash Prompt In Linux.md deleted file mode 100644 index 267e2b85e2..0000000000 --- a/sources/tech/20181119 How To Customize Bash Prompt In Linux.md +++ /dev/null @@ -1,300 +0,0 @@ -HankChow translating - -How To Customize Bash Prompt In Linux -====== - - -As you know already, **BASH** (the **B** ourne- **A** gain **Sh** ell) is the default shell for most modern Linux distributions. In this guide, we are going to customize BASH prompt and enhance its look by adding some colors and styles. Of course, there are many plugins/tools available to get this job done easily and quickly. However, we still can do some basic customization, such as adding, modifying elements, changing the foreground and background color etc., without having to install any additional tools and plugins. Let us get started! - -### Customize Bash Prompt In Linux - -In BASH, we can customize and change the BASH prompt as the way you want by changing the value of **PS1** environment variable. - -Usually, the BASH prompt will look something like below: - - -Here, **sk** is my username and **ubuntuserver** is my hostname. - -Now, we are going to change this prompt as per your liking by inserting some backslash-escaped special characters called **Escape Sequences**. - -Let me show you some examples. - -Before going further, it is highly recommended to backup the **~/.bashrc** file. - -``` -$ cp ~/.bashrc ~/.bashrc.bak -``` - -**Modify “[[email protected]][1]” part in the Bash prompt** - -As I mentioned above, the BASH prompt has “[[email protected]][1]” part by default in most Linux distributions. You can change this part to something else. - -To do so, edit **~/.bashrc **file: - -``` -$ vi ~/.bashrc -``` - -Add the following line at the end: - -``` -PS1="ostechnix> " -``` - -Replace “ostechnix” with any letters/words of your choice. Once added, hit the **ESC** key and type **:wq** to save and exit the file. - -Run the following command to update the changes: - -``` -$ source ~/.bashrc -``` - -Now, the BASH prompt will have the letters “ostechnix” in the shell prompt. - -![][3] - -Here is another example. I am going to replace “[[email protected]][1]” part with “[[email protected]][1]>”. - -To do so, add the following entry in your **~./bashrc** file. - -Don’t forget to update the changes using “source ~./bashrc” command. - -Here is the output of my BASH prompt in Ubuntu 18.04 LTS. - - -**Display username only:** - -To display the username only, just add the following line in **~/.bashrc** file. - -``` -export PS1="\u " -``` - -Here, **\u** is the escape sequence. - -Here are some more values to add to your PS1 variable to change the BASH prompt. After adding each entry, you must run “source ~/.bashrc” command to take effect the changes. - -**Add username with hostname:** - -``` -export PS1="\u\h " -``` - -Your prompt will now look like below: - -``` -skubuntuserver -``` - -**Add username and FQDN (Fully Qualified Domain Name):** - -``` -export PS1="\u\H " -``` - -**Add extra characters between username and hostname:** - -If you want to any letter, for example **@** , between the username and hostname, use the following entry: - -``` -export PS1="\u@\h " -``` - -The bash prompt will look like below: -``` -sk@ubuntuserver -``` - -**Add username with hostname with $ symbol at the end:** -``` -export PS1="\u@\h\\$ " -``` - -**Add special characters between and after username and hostname:** -``` -export PS1="\u@\h> " -``` - -This entry will change the BASH prompt as shown below. -``` -sk@ubuntuserver> -``` - -Similarly, you can add other special characters, such as colon, semi-colon, *, underscore, space etc. - -**Display username, hostname, shell name:** -``` -export PS1="\u@\h>\s " -``` - -**Display username, hostname, shell and and its version:** -``` -export PS1="\u@\h>\s\v " -``` - -Bash prompt output: - -![][4] - -Display username, hostname and path to current directory: -``` -export PS1="\u@\h\w " -``` - -You will see a tilde (~) symbol if the current directory is $HOME. - -**Display date in BASH prompt:** - -To display date with your username and hostname in the BASH prompt, add the following entry in ~/.bashrc file. -``` -export PS1="\u@\h>\d " -``` -![][5] - -**Date and time in 12 hour format in BASH prompt:** -``` -export PS1="\u@\h>\d\@ " -``` - -**Date and 12 hour time hh:mm:ss format:** -``` -export PS1="\u@\h>\d\T " -``` - -**Date and 24 hour time:** -``` -export PS1="\u@\h>\d\A " -``` - -**Date and 24 hour hh:mm:ss format:** -``` -export PS1="\u@\h>\d\t " -``` - -These are some common escape sequences to change the Bash prompt format. There are few more escape sequences are available. You can view them all in in the **bash man page** under the **“PROMPTING”** section. - -And, you can view the current prompt settings at any time using command: - -``` -$ echo $PS1 -``` - -**Hide “username@hostname” Part In Bash prompt** - -I don’t want to change anything. Can I hide it altogether? Yes, you can! - -If you’re a blogger or tech writer, there are chances that you have to upload the screenshots of your Linux Terminal in your websites and blogs. Your username/hostname might be too cool, so you may not want others to copy and use them as their own. On the other hand, your username/hostname might be too weird or too bad or contain offensive characters, so you don’t want others to view them. In such cases, this small tip might help you to hide or modify “[[email protected]][1]” part in Terminal. - -If you don’t like to let the users to view your username/hostname part, just follow the steps given below. - -Edit your **“~/.bashrc”** file: - -``` -$ vi ~/.bashrc -``` - -Add the following at the end: - -``` -PS1="\W> " -``` - -Type **:wq** to save and close the file. - -Then, run the following command to take effect the changes. - -``` -$ source ~/.bashrc -``` - -That’s it. Now, check your Terminal. You will not see the [[email protected]][1] part. You will only see the **~ >** symbol. - -![][6] - -Want to know another simplest way without messing the **~/.bashrc** file? Just create another user account something like **[[email protected]][1]** , or **[[email protected]][1]**. Use these accounts for making guides, videos and upload them on your blog or online. Now, you have nothing to worry about your identity. - -**Warning:** This is a bad practice in some cases. For example, if another shells like zsh inherits your current shell, it will cause some problems. Use it only for hiding or modifying your [[email protected]][1] part if you use single shell. Apart from hiding the [[email protected]][1] part in the Terminal, this tip is pretty useless and might be problematic. - -### Colorizing BASH prompt - -What we have seen so far is we just changed/added some elements to the BASH prompt. In this section, we are going to add colors the elements. - -You can enhance the foreground (text) and background color of BASH prompt’s elements by adding some code to the ~/.bashrc file. - -For example, to change the foreground color of all texts to Red, add the following code: -``` -export PS1="\u@\[\e[31m\]\h\[\e[m\] " -``` - -Once added, update the changes using command: - -Now, your BASH prompt will look like below: -![][7] - -Similarly, to change the background color, add this code: -``` -export PS1="\u@\[\e[31;46m\]\h\[\e[m\] " -``` - -![][8] - -### **Adding Emojis** - -Who doesn’t love emoji? We can add an emoji by placing the following code in the ~/.bashrc file. - -``` -PS1="\W 🔥 >" -``` - -Please note that some terminal may not show the emojis properly depending upon the font used. You may see either garbled characters or monochrome emoji if you don’t have suitable fonts. - -### Customizing BASH is bit difficult to me, Is there any other easy way? - -If you’re a newbie, writing and adding PS1 values will be confusing and difficult. Also, you will find it bit difficult to arrange the elements to get the result of your choice. No worries! There is an online Bash PS1 generator available which allows you to easily generate different PS1 values as you wish. - -Go to the following website: - -[][9] - -Just pick the elements you want to use in your BASH prompt. Add the colors to the elements and re-arrange them in any order of your liking. Preview the output instantly and finally copy/paste resulting code in your **~/.bashrc** file. It is that simple! Most of the examples mentioned in this guide are taken from this website. - - -### I messed up with my .bashrc file? How to restore it to default settings? - -As I mentioned earlier, it is strongly recommended to take backup ~./bashrc (Or any important configuration files in general) before making any changes. So, you can restore it to the previous working version if something went wrong. However if you forgot to backup the ~/.bashrc file in the first place, you still can restore it to the default settings as described in the following guide. - -[How To Restore .bashrc File To Default Settings][10] - -The above guide is based on Ubuntu, but it may applicable to other Linux distributions as well. Please let us be clear that the aforementioned guide will help you to reset ~/.bashrc to its default settings at the time of new installation. Any changes done afterwards will be lost. - -And, that’s all for now. I will keep updating this guide as I learned more ways to customize the BASH prompt in future. - -Hope this helps. More good stuffs to come. Stay tuned! - -Cheers! - - - --------------------------------------------------------------------------------- - -via: https://www.ostechnix.com/hide-modify-usernamelocalhost-part-terminal/ - -作者：[SK][a] -选题：[lujun9972][b] -译者：[译者ID](https://github.com/译者ID) -校对：[校对者ID](https://github.com/校对者ID) - -本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 - -[a]: https://www.ostechnix.com/author/sk/ -[b]: https://github.com/lujun9972 -[1]: https://www.ostechnix.com/cdn-cgi/l/email-protection -[2]: data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7 -[3]: http://www.ostechnix.com/wp-content/uploads/2017/10/Linux-Terminal-2.png -[4]: http://www.ostechnix.com/wp-content/uploads/2017/10/bash-prompt-2.png -[5]: http://www.ostechnix.com/wp-content/uploads/2017/10/bash-prompt-3.png -[6]: http://www.ostechnix.com/wp-content/uploads/2017/10/Linux-Terminal-1.png -[7]: http://www.ostechnix.com/hide-modify-usernamelocalhost-part-terminal/bash-prompt-4/ -[8]: http://www.ostechnix.com/hide-modify-usernamelocalhost-part-terminal/bash-prompt-5/ -[9]: http://ezprompt.net/ -[10]: https://www.ostechnix.com/restore-bashrc-file-default-settings-ubuntu/ diff --git a/sources/tech/20181120 How To Change GDM Login Screen Background In Ubuntu.md b/sources/tech/20181120 How To Change GDM Login Screen Background In Ubuntu.md deleted file mode 100644 index 1b35fd563d..0000000000 --- a/sources/tech/20181120 How To Change GDM Login Screen Background In Ubuntu.md +++ /dev/null @@ -1,85 +0,0 @@ -Translating by Guevaraya -How To Change GDM Login Screen Background In Ubuntu -====== -Whenever you log in or lock and unlock your Ubuntu 18.04 LTS desktop, you will be greeted with a plain purple-colored screen. It is the default GDM (GNOME Display Manager) background since Ubuntu version 17.04. Some of you may feel boring to look at this plain background and want to make the Login screen something cool and eye-candy! If so, you’re on the right track. This brief guide describes how to change GDM Login screen background in Ubuntu 18.04 LTS desktop. - -### Change GDM Login Screen Background In Ubuntu - -Here is how the default GDM login screen background image looks like in Ubuntu 18.04 LTS desktop. - - -Whether you like it or not, you will stumbled upon this screen every time you log in or lock and unlock the system. No worries! You can change this background with any beautiful image of your choice. - -Changing desktop wallpaper and user’s profile picture is not a big deal in Ubuntu. We can do it with a few mouse clicks in no time. However, changing Login/Lock screen background need a little bit editing of a file called **ubuntu.css** located under **/usr/share/gnome-shell/theme** directory. - -Before modifying this file, take a backup of this file. So, we can restore it if something went wrong. - -``` -$ sudo cp /usr/share/gnome-shell/theme/ubuntu.css /usr/share/gnome-shell/theme/ubuntu.css.bak -``` - -Now, edit ubuntu.css file: - -``` -$ sudo nano /usr/share/gnome-shell/theme/ubuntu.css -``` - -Find the following lines under the directive named **“lockDialogGroup”** in the file: - -``` -#lockDialogGroup { - background: #2c001e url(resource:///org/gnome/shell/theme/noise-texture.png); - background-repeat: repeat; -} -``` - - -As you can see, the default image for the GDM login screen is **noise-texture.png**. - -Now, change the background image by adding your image path. You can use either .jpg or .png file. Both format images worked fine for me. After editing the file, the contents of file will look like below: - -``` -#lockDialogGroup { - background: #2c001e url(file:///home/sk/image.png); - background-repeat: no-repeat; - background-size: cover; - background-position: center; -} -``` - -Please pay little attention to the modified version of this directive in the ubuntu.css file. I have marked the changes in bold. - -As you might have noticed, I have changed the line “… **url(resource:///org/gnome/shell/theme/noise-texture.png);** ” with “ **…url(file:///home/sk/image.png);”**. I.e You should change “… **url(resource** …” to “… **url(file**..”. - -Also, I have changed the value of “background-repeat:” parameter from **“repeat”** to **“no-repeat”** and added two more lines. You can simply copy/paste the above lines and change image path with your own in your ubuntu.css file. - -Once you are done, save and close the file. And, reboot your system. - -Here is my GDM login screen with updated backgrounds: - - - - -Cool, yeah? As you can see, changing GDM login screen is not that difficult either. All you have to do is to change the path of the image in ubuntu.css file and restart your system. It is simple as that. Have fun! - -You can also edit **gdm3.css** file located under **/usr/share/gnome-shell/theme** directory and modify it as shown above to get the same result. Again, don’t forget to take the backup of the file before making any changes. - -And, that’s all now. More good stuffs to come. Stay tuned! - -Cheers! - - - --------------------------------------------------------------------------------- - -via: https://www.ostechnix.com/how-to-change-gdm-login-screen-background-in-ubuntu/ - -作者：[SK][a] -选题：[lujun9972][b] -译者：[译者ID](https://github.com/译者ID) -校对：[校对者ID](https://github.com/校对者ID) - -本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 - -[a]: https://www.ostechnix.com/author/sk/ -[b]: https://github.com/lujun9972 diff --git a/sources/tech/20181121 Coupled commands with control operators in Bash.md b/sources/tech/20181121 Coupled commands with control operators in Bash.md new file mode 100644 index 0000000000..b599dc64af --- /dev/null +++ b/sources/tech/20181121 Coupled commands with control operators in Bash.md @@ -0,0 +1,129 @@ +Translating by Jamskr + +Coupled commands with control operators in Bash +====== +Add logic to the command line with control operators in compound commands. + + + +Simple compound commands—such as stringing several commands together in a sequence on the command line—are used often. Such commands are separated by semicolons, which define the end of a command. To create a simple series of shell commands on a single line, simply separate each command using a semicolon, like this: + +``` +command1 ; command2 ; command3 ; command4 ; +``` + +You don't need to add a final semicolon because pressing the Enter key implies the end of the final command, but it's fine to add it for consistency. + +**& &** and **||** control operators built into Bash. These two control operators provide some flow control and enable us to alter the code-execution sequence. The semicolon and the **newline** character are also considered to be Bash control operators. + +All the commands will run without a problem—as long as no error occurs. But what happens if an error happens? We can anticipate and allow for errors using theandcontrol operators built into Bash. These two control operators provide some flow control and enable us to alter the code-execution sequence. The semicolon and thecharacter are also considered to be Bash control operators. + +The **& &** operator simply says "if command1 is successful, then run command2." If command1 fails for any reason, command2 won't run. That syntax looks like: + +``` +command1 && command2 +``` + +This works because every command returns a code to the shell that indicates whether it completed successfully or failed during execution. By convention, a return code (RC) of 0 (zero) indicates success and any positive number indicates some type of failure. Some sysadmin tools just return a 1 to indicate any failure, but many use other positive numerical codes to indicate the type of failure. + +The Bash shell's **$?** variable can be checked very easily by a script, by the next command in a list of commands, or even directly by a sysadmin. Let's look at RCs. We can run a simple command and immediately check the RC, which will always pertain to the last command that ran. + +``` +[student@studentvm1 ~]$ ll ; echo "RC = $?" +total 284 +-rw-rw-r-- 1 student student 130 Sep 15 16:21 ascii-program.sh +drwxrwxr-x 2 student student 4096 Nov 10 11:09 bin + +drwxr-xr-x. 2 student student 4096 Aug 18 10:21 Videos +RC = 0 +[student@studentvm1 ~]$ +``` + +This RC is 0, which means the command completed successfully. Now try the same command on a directory where we don't have permissions. + +``` +[student@studentvm1 ~]$ ll /root ; echo "RC = $?" +ls: cannot open directory '/root': Permission denied +RC = 2 +[student@studentvm1 ~]$ +``` + +This RC's meaning can be found in the [**ls** command's man page][1]. + +Let's try the **& &** control operator as it might be used in a command-line program. We'll start with something simple: Create a new directory and, if that is successful, create a new file in it. + +We need a directory where we can create other directories. First, create a temporary directory in your home directory where you can do some testing. + +``` +[student@studentvm1 ~]$ cd ; mkdir testdir +``` + +Create a new directory in **~/testdir** , which should be empty because you just created it, and then create a new, empty file in that new directory. The following command will do those tasks. + +``` +[student@studentvm1 ~]$ mkdir ~/testdir/testdir2 && touch ~/testdir/testdir2/testfile1 +[student@studentvm1 ~]$ ll ~/testdir/testdir2/ +total 0 +-rw-rw-r-- 1 student student 0 Nov 12 14:13 testfile1 +[student@studentvm1 ~]$ +``` + +We know everything worked as it should because the **testdir** directory is accessible and writable. Change the permissions on **testdir** so it is no longer accessible to the user **student** as follows: + +``` +[student@studentvm1 ~]$ chmod 076 testdir ; ll | grep testdir +d---rwxrw-. 3 student student 4096 Nov 12 14:13 testdir +[student@studentvm1 ~]$ +``` + +Using the **grep** command after the long list ( **ll** ) shows the listing for **testdir**. You can see that the user **student** no longer has access to the **testdir** directory. Now let's run almost the same command as before but change it to create a different directory name inside **testdir**. + +``` +[student@studentvm1 ~]$ mkdir ~/testdir/testdir3 && touch ~/testdir/testdir3/testfile1 +mkdir: cannot create directory ‘/home/student/testdir/testdir3’: Permission denied +[student@studentvm1 ~]$ +``` + +Although we received an error message, using the **& &** control operator prevents the **touch** command from running because there was an error in creating **testdir3**. This type of command-line logical flow control can prevent errors from compounding and making a real mess of things. But let's make it a little more complicated. + +The **||** control operator allows us to add another command that executes when the initial program statement returns a code larger than zero. + +``` +[student@studentvm1 ~]$ mkdir ~/testdir/testdir3 && touch ~/testdir/testdir3/testfile1 || echo "An error occurred while creating the directory." +mkdir: cannot create directory ‘/home/student/testdir/testdir3’: Permission denied +An error occurred while creating the directory. +[student@studentvm1 ~]$ +``` + +Our compound command syntax using flow control takes this general form when we use the **& &** and **||** control operators: + +``` +preceding commands ; command1 && command2 || command3 ; following commands +``` + +The compound command using the control operators may be preceded and followed by other commands that can be related to the ones in the flow-control section but which are unaffected by the flow control. All of those commands will execute without regard to anything that takes place inside the flow-control compound command. + +These flow-control operators can make working at the command line more efficient by handling decisions and letting us know when a problem has occurred. I use them directly on the command line as well as in scripts. + +You can clean up as the root user to delete the directory and its contents. + +``` +[root@studentvm1 ~]# rm -rf /home/student/testdir +``` + +How do you use Bash control operators? Let us know in the comment section. + +-------------------------------------------------------------------------------- + +via: https://opensource.com/article/18/11/control-operators-bash-shell + +作者：[David Both][a] +选题：[lujun9972][b] +译者：[译者ID](https://github.com/译者ID) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]: https://opensource.com/users/dboth +[b]: https://github.com/lujun9972 +[1]: http://man7.org/linux/man-pages/man1/ls.1.html diff --git a/sources/tech/20181121 How to swap Ctrl and Caps Lock keys in Linux.md b/sources/tech/20181121 How to swap Ctrl and Caps Lock keys in Linux.md new file mode 100644 index 0000000000..c9f24938ff --- /dev/null +++ b/sources/tech/20181121 How to swap Ctrl and Caps Lock keys in Linux.md @@ -0,0 +1,113 @@ +Translating by jlztan + +How to swap Ctrl and Caps Lock keys in Linux +====== +Linux desktop environments make it easy to set up your keyboard as you want it. Here's how. + + +For many people who've been computer users for (let's just say) "quite some time now," the Ctrl and Caps Lock keys have been in the wrong place since shortly after the first PC keyboards rolled off the production line. For me, the correct positioning appears in this image of a vintage 1995 Sun Workstation keyboard. (Forgive me for the blurriness of the image; it was taken with a Minox spy camera in low light.) + +If you're interested, you can read about the [history of the Ctrl key location][1]. I'm not going to discuss the various rationales for placing the Ctrl key next to the "a" key versus below the Shift key; I'm not going to comment on the overall uselessness of the Caps Lock key (whoops); and I'm not going to argue with those who advocate using the heel of the hand to activate the Ctrl key, even though it's impossible to do on some laptop keyboards where the keys are inset below the level of the wrist rest (whoops). + +Rather, I'm going to assume I'm not the only one who prefers the Ctrl key next to the "a" and describe how to use the wonderful flexibility that comes with Linux to swap the Ctrl and Caps Lock keys on various desktop environments. Note that this kind of advice seems to have a limited shelf life, as tools for tweaking desktop settings change fairly often. But I hope this offers a good place for you to start. + +### With GNOME 3 + +[GNOME 3][2] desktop environment users can use the [Tweaks][3] tool to swap their Caps Lock and Ctrl keys, as you can see below. + +Here's how to do it: + + 1. Install the Tweaks tool from your distribution's repositories. + 2. Start the Tweaks application. + 3. Select "Keyboard & Mouse" from the left-hand menu. + 4. Click "Additional Layout Options". + 5. Click "Ctrl position" on the window that opens and choose "Swap Ctrl and Caps Lock." + + + +That's it! By the way, you can do lots of cool stuff with the Tweaks tool. For example, I set my right Ctrl key to be a Compose key, which allows me to type all sorts of characters with keyboard shortcuts—such as ç, é, ô, and ñ and with the keystrokes Compose+c+Comma; Compose+e+Right quote; Compose+o+Circumflex; and Compose+n+Tilde. + +### With KDE + +I don't use [KDE][4], but item 5 in this article about [KDE tweaks that will change your life][5] by my colleague Seth Kenlon will show you how to remap your keys. + +### With Xfce + +As far as I can tell, the [Xfce][6] desktop environment doesn't have a handy tool for managing these kinds of settings. However, the **ctrl:swapcaps** option to the **setxkbmap** command will help you make these changes. This type of modification has two parts: + + 1. Figuring out the command's usage; + 2. Figuring out where to invoke the command so it is activated as the desktop comes up. + + + +The first part is pretty straightforward: the command is: + +``` +/usr/bin/setxkbmap -option "ctrl:nocaps" +``` + +It's worth executing this in a terminal window to make sure the results are what you expect. + +Assuming it works, where should you invoke the command? That requires some experimentation; one possibility is in the file **.profile** in the user's home directory. Another option is to add the command to the autostart facility in Xfce (look for "Session and Startup" in the Settings Manager). + +Another possibility is to use the same option in the file / **etc/default/keyboard** , which might end up looking like this: + +``` +# KEYBOARD CONFIGURATION FILE + +# Consult the keyboard(5) manual page. + +XKBMODEL="pc105" +XKBLAYOUT="us" +XKBVARIANT="" +XKBOPTIONS="ctrl:swapcaps" + +BACKSPACE="guess" +``` + +Note that this kind of change will affect all users, so if you share your computer, be prepared to do some explaining. Also, system updates may overwrite this file, so you'll need to edit it again if your setup stops working. Putting the same information in the file **.keyboard** in the user's home directory might accomplish the same task on the user's behalf. + +Finally, note that these kinds of changes require you to restart Xfce (except when running the command on the command line in the terminal window, but that won't stick past the end of the session). + +### With LXQt and other desktop environments + +I haven't tried [LXQt][7], but if my memory serves from [LXDE][8], I would try the same recipe used above for Xfce. I'd also expect that the Xfce recipe could work for other Linux desktop environments, but, of course, your favorite search engine is always your friend. + +### The console + +I haven't tried this, as I have very few opportunities to interact with the console (what you see on a server or when your window system doesn't come up properly). The recipes presented above affect the terminal window in the way one would hope, i.e., consistently with other applications. + +However, if the file **/etc/default/keyboard** or **~/.keyboard** has already been edited (as described above), the utility **setupcon** is intended to change the console keyboard setup so it functions the same way.** **This [StackExchange article][9], [this other one][10], and [this third one][11] give some ideas on how to effect these changes from both of these files. The third article also talks about using **dumpkeys** and **loadkeys**. It's also worthwhile to read [the setupcon man page][12] — it's short and to the point, and combined with the comments from the StackExchange articles, should be enough to get a solution in place. + +Finally, it's worth emphasizing here the point mentioned in the StackExchange articles - configuring the console IS NOT THE SAME as configuring terminal windows; the latter are configured through the desktop manager as described previously. + +### When all else fails + +The manual pages for **setxkbmap** , **xkeyboard-config** , **keyboard** , **console-setup** , and **setupcon** are all useful references. Or, if you don't like reading manual pages, there's [this great article][13]. + +-------------------------------------------------------------------------------- + +via: https://opensource.com/article/18/11/how-swap-ctrl-and-caps-lock-your-keyboard + +作者：[Chris Hermansen][a] +选题：[lujun9972][b] +译者：[译者ID](https://github.com/译者ID) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]: https://opensource.com/users/clhermansen +[b]: https://github.com/lujun9972 +[1]: https://en.wikipedia.org/wiki/Control_key +[2]: https://www.gnome.org/gnome-3/ +[3]: https://wiki.gnome.org/Apps/Tweaks +[4]: https://www.kde.org/ +[5]: https://opensource.com/article/17/5/7-cool-kde-tweaks-will-improve-your-life +[6]: https://www.xfce.org/ +[7]: https://lxqt.org/ +[8]: https://lxde.org/ +[9]: https://askubuntu.com/questions/485454/how-to-remap-keys-on-a-user-level-both-with-and-without-x +[10]: https://unix.stackexchange.com/questions/198791/how-do-i-permanently-change-the-console-tty-font-type-so-it-holds-after-reboot +[11]: https://superuser.com/questions/290115/how-to-change-console-keymap-in-linux +[12]: http://man.he.net/man1/setupcon +[13]: http://www.noah.org/wiki/CapsLock_Remap_Howto diff --git a/sources/tech/20181122 Getting started with Jenkins X.md b/sources/tech/20181122 Getting started with Jenkins X.md new file mode 100644 index 0000000000..1c2aab6903 --- /dev/null +++ b/sources/tech/20181122 Getting started with Jenkins X.md @@ -0,0 +1,148 @@ +[#]: collector: (lujun9972) +[#]: translator: ( ) +[#]: reviewer: ( ) +[#]: publisher: ( ) +[#]: subject: (Getting started with Jenkins X) +[#]: via: (https://opensource.com/article/18/11/getting-started-jenkins-x) +[#]: author: (Dave Johnson https://opensource.com/users/snoopdave) +[#]: url: ( ) + +Getting started with Jenkins X +====== +Jenkins X provides continuous integration, automated testing, and continuous delivery to Kubernetes. + + +[Jenkins X][1] is an open source system that offers software developers continuous integration, automated testing, and continuous delivery, known as CI/CD, in Kubernetes. Jenkins X-managed projects get a complete CI/CD process with a Jenkins pipeline that builds and packages project code for deployment to Kubernetes and access to pipelines for promoting projects to staging and production environments. + +Developers are already benefiting from running "classic" open source Jenkins and CloudBees Jenkins on Kubernetes, thanks in part to the Jenkins Kubernetes plugin, which allows you to dynamically spin-up Kubernetes pods to run Jenkins build agents. Jenkins X adds what's missing from Jenkins: comprehensive support for continuous delivery and managing the promotion of projects to preview, staging, and production environments running in Kubernetes. + +This article is a high-level explanation of how Jenkins X works; it assumes you have some knowledge of Kubernetes and classic Jenkins. + +### What you get with Jenkins X + +If you're running on one of the major cloud providers (Amazon Elastic Container Service for Kubernetes, Google Kubernetes Engine, or Microsoft Azure Kubernetes Service), installing and deploying Jenkins X is easy. Download the Jenkins X command-line interface and run the **jx create cluster** command. You'll be prompted for the necessary information and, if you take the defaults, Jenkins X will create a starter-size Kubernetes cluster and install Jenkins X. + +When you deploy Jenkins X, a number of services are put in motion to watch your Git repositories and respond by building, testing, and promoting your applications to staging, production, and other environments you define. Jenkins X also deploys a set of supporting services, including [Jenkins][2], [Docker Registry][3], [Chart Museum][4], and [Monocular][5] to manage [Helm][6] charts, and [Nexus][7], which serves as a Maven and npm repository. + +The Jenkins X deployment also creates two Git repositories, one for your staging environment and one for production. These are in addition to the Git repositories you use to manage your project source code. Jenkins X uses these repositories to manage what is deployed to each environment, and promotions are done via Git pull requests (PRs)—this approach is known as [GitOps][8]. Each repository contains a Helm chart that specifies the applications to be deployed to the corresponding environment. Each repository also has a Jenkins pipeline to handle promotions. + +### Creating a new project with Jenkins X + +To create a new project with Jenkins X, use the **jx create quickstart** command. If you don't specify any options, jx will prompt you to select a project name and a platform—which can be just about anything. SpringBoot, Go, Python, Node, ASP.NET, Rust, Angular, and React are all supported, and the list keeps growing. Once you have chosen your project name and platform, Jenkins X will: + + * Create a new project that includes a "hello-world"-style web project + * Add the appropriate type of makefile or build script for the chosen platform + * Add a Jenkinsfile to manage promotions to staging and production environments + * Add a Dockerfile and Helm charts, created via [Draft][9] + * Add a [Skaffold][10] configuration for deploying the application to Kubernetes + * Create a Git repository and push the new project code there + + + +Next, a webhook from Git will notify Jenkins X that a project changed, and it will run your project's Jenkins pipeline to build and push your Docker image and Helm charts. + +Finally, the pipeline will submit a PR to the staging environment's Git repository with the changes needed to promote the application. + +Once the PR is merged, the staging pipeline will run to apply those changes and do the promotion. A couple of minutes after creating your project, you'll have end-to-end CI/CD, and your project will be running in staging and available for use. + +![Developer commits changes, project deployed to staging][12] + +Developer commits changes, project deployed to the staging environment. + +The figure above illustrates the repositories, registries, and pipelines and how they interact in a Jenkins X promotion to staging. Here are the steps: + + 1. The developer commits and pushes the change to the project's Git repository + 2. Jenkins X is notified and runs the project's Jenkins pipeline in a Docker image that includes the project's language and supporting frameworks + 3. The project pipeline builds, tests, and pushes the project's Helm chart to Chart Museum and its Docker image to the registry + 4. The project pipeline creates a PR with changes needed to add the project to the staging environment + 5. Jenkins X automatically merges the PR to Master + 6. Jenkins X is notified and runs the staging pipeline + 7. The staging pipeline runs Helm, which deploys the environment, pulling Helm charts from Chart Museum and Docker images from the Docker registry. Kubernetes creates the project's resources, typically a pod, service, and ingress. + + + +### Importing your existing projects into Jenkins X + +**jx import** , Jenkins X adds the things needed for your project to be deployed to Kubernetes and participate in CI/CD. It will add a Jenkins pipeline, Helm charts, and a Skaffold configuration for deploying the application to Kubernetes. Jenkins X will create a Git repository and push the changes there. Next, a webhook from Git will notify Jenkins X that a project changed, and promotion to staging will happen as described above for new projects. + +### Promoting your project to production + +When you import a project via, Jenkins X adds the things needed for your project to be deployed to Kubernetes and participate in CI/CD. It will add a Jenkins pipeline, Helm charts, and a Skaffold configuration for deploying the application to Kubernetes. Jenkins X will create a Git repository and push the changes there. Next, a webhook from Git will notify Jenkins X that a project changed, and promotion to staging will happen as described above for new projects. + +To promote a version of your project to the production environment, use the **jx promote** command. This command will prepare a Git PR that contains the Helm chart changes needed to deploy into the production environment and submit this request to the production environment's Git repository. Once the request is manually approved, Jenkins X will run the production pipeline to deploy your project via Helm. + +![Promoting project to production][14] + +Developer promotes the project to production. + +This figure illustrates the repositories, registries, and pipelines and how they interact in a Jenkins X promotion to production. Here are the steps: + + 1. The developer runs the **jx promote** command to promote a project to production + 2. Jenkins X creates a PR with changes needed to add the project to the production environment + 3. The developer manually approves the PR, and it is merged to Master + 4. Jenkins X is notified and runs the production pipeline + 5. The production pipeline runs Helm, which deploys the environment, pulling Helm charts from Chart Museum and Docker images from the Docker registry. Kubernetes creates the project's resources, typically a pod, service, and ingress. + + + +### Other features of Jenkins X + +Other interesting and appealing features of Jenkins X include: + +#### Preview environments + +When you create a PR to add a new feature to your project, you can ask Jenkins X to create a preview environment so you can make your new feature available for preview and testing before the PR is merged. + +#### Extensions + +It is possible to create extensions to Jenkins X. An extension is code that runs at specific times in the CI/CD process. An extension can provide code that runs when the extension is installed, uninstalled, as well as before and after each pipeline. + +#### Serverless Jenkins + +Instead of running the Jenkins web application, which continually consumes CPU and memory resources, you can run Jenkins only when you need it. During the past year, the Jenkins community created a version of Jenkins that can run classic Jenkins pipelines via the command line with the configuration defined by code instead of HTML forms. + +This capability is now available in Jenkins X. When you create a Jenkins X cluster, you can choose to use Serverless Jenkins. If you do, Jenkins X will deploy [Prow][15] to handle webhooks from GitHub and [Knative][16] to run Jenkins pipelines. + +### Jenkins X limitations + +Jenkins X also has some limitations that should be considered: + + * **Jenkins X is currently limited to projects that use Git:** Jenkins X is opinionated about CI/CD and assumes everybody wants to run and deploy software to Kubernetes and everybody is happy to use Git for source code and defining environments. Also, the Serverless Jenkins feature currently works only with GitHub. + * **Jenkins X is limited to Kubernetes:** It is true that Jenkins X can run automated builds, testing, and continuous integration for any type of software, but the continuous delivery part targets a Kubernetes namespace managed by Jenkins X. + * **Jenkins X requires cluster-admin level Kubernetes access:** Jenkins X needs cluster-admin access so it can define and manage a Kubernetes custom resource definition. Hopefully, this is a temporary limitation, because it could be a show-stopper for some. + + + +### Conclusions + +Jenkins X looks to be a good way to implement CI/CD for Kubernetes, and I'm looking forward to putting it to the test in production. Using Jenkins X is also a good way to learn about some useful open source tools for deploying to Kubernetes, including Helm, Draft, Skaffold, Prow, and more. These are things you might want to use even if you decide Jenkins X is not for you. If you're deploying to Kubernetes, take Jenkins X for a spin. + +-------------------------------------------------------------------------------- + +via: https://opensource.com/article/18/11/getting-started-jenkins-x + +作者：[Dave Johnson][a] +选题：[lujun9972][b] +译者：[译者ID](https://github.com/译者ID) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]: https://opensource.com/users/snoopdave +[b]: https://github.com/lujun9972 +[1]: https://jenkins-x.io/ +[2]: https://jenkins.io/ +[3]: https://docs.docker.com/registry/ +[4]: https://github.com/helm/chartmuseum +[5]: https://github.com/helm/monocular +[6]: https://helm.sh +[7]: https://www.sonatype.com/nexus-repository-oss +[8]: https://www.weave.works/blog/gitops-operations-by-pull-request +[9]: https://draft.sh/ +[10]: https://github.com/GoogleContainerTools/skaffold +[11]: /file/414941 +[12]: https://opensource.com/sites/default/files/uploads/jenkinsx_fig1.png (Developer commits changes, project deployed to staging) +[13]: /file/414946 +[14]: https://opensource.com/sites/default/files/uploads/jenkinsx_fig2.png (Promoting project to production) +[15]: https://github.com/kubernetes/test-infra/tree/master/prow +[16]: https://cloud.google.com/knative/ diff --git a/sources/tech/20181123 How to Build a Netboot Server, Part 1.md b/sources/tech/20181123 How to Build a Netboot Server, Part 1.md new file mode 100644 index 0000000000..01bc4a49dd --- /dev/null +++ b/sources/tech/20181123 How to Build a Netboot Server, Part 1.md @@ -0,0 +1,461 @@ +[#]: collector: (lujun9972) +[#]: translator: ( ) +[#]: reviewer: ( ) +[#]: publisher: ( ) +[#]: subject: (How to Build a Netboot Server, Part 1) +[#]: via: (https://fedoramagazine.org/how-to-build-a-netboot-server-part-1/) +[#]: author: (Gregory Bartholomew https://fedoramagazine.org/author/glb/) +[#]: url: ( ) + +How to Build a Netboot Server, Part 1 +====== + + + +Some computer networks need to maintain identical software installations and configurations on several physical machines. One such environment would be a school computer lab. A [netboot][1] server can be set up to serve an entire operating system over a network so that the client computers can be configured from one central location. This tutorial will show one method of building a netboot server. + +Part 1 of this tutorial will cover creating a netboot server and image. Part 2 will show how to add Kerberos-authenticated home directories to the netboot configuration. + +### Initial Configuration + +Start by downloading one of Fedora Server’s [netinst][2] images, burning it to a CD, and booting the server that will be reformatted from it. We just need a typical “Minimal Install” of Fedora Server for our starting point and we will use the command line to add any additional packages that are needed after the installation is finished. + +![][3] + +> NOTE: For this tutorial we will be using Fedora 28. Other versions may include a slightly different set of packages in their “Minimal Install”. If you start with a different version of Fedora, then you may need to do some troubleshooting if an expected file or command is not available. + +Once you have your minimal installation of Fedora Server up and running, log in as root and set the hostname: + +``` +$ MY_HOSTNAME=server-01.example.edu +$ hostnamectl set-hostname $MY_HOSTNAME +``` + +> NOTE: Red Hat recommends that both static and transient names match the fully-qualified domain name (FQDN) used for the machine in DNS, such as host.example.com ([Understanding Host Names][4]). +> +> NOTE: This guide is meant to be copy-and-paste friendly. Any value that you might need to customize will be stated as a MY_* variable that you can tweak before running the remaining commands. Beware that if you log out, the variable assignments will be cleared. +> +> NOTE: Fedora 28 Server tends to dump a lot of logging output to the console by default. You may want to disable the console logging temporarily by running: sysctl -w kernel.printk=0 + +Next, we need a static network address on our server. The following sequence of commands should find and reconfigure your default network connection appropriately: + +``` +$ MY_DNS1=192.0.2.91 +$ MY_DNS2=192.0.2.92 +$ MY_IP=192.0.2.158 +$ MY_PREFIX=24 +$ MY_GATEWAY=192.0.2.254 +$ DEFAULT_DEV=$(ip route show default | awk '{print $5}') +$ DEFAULT_CON=$(nmcli d show $DEFAULT_DEV | sed -n '/^GENERAL.CONNECTION:/s!.*:\s*!! p') +$ nohup bash << END +nmcli con mod "$DEFAULT_CON" connection.id "$DEFAULT_DEV" +nmcli con mod "$DEFAULT_DEV" connection.interface-name "$DEFAULT_DEV" +nmcli con mod "$DEFAULT_DEV" ipv4.method disabled +nmcli con up "$DEFAULT_DEV" +nmcli con add con-name br0 ifname br0 type bridge +nmcli con mod br0 bridge.stp no +nmcli con mod br0 ipv4.dns $MY_DNS1,$MY_DNS2 +nmcli con mod br0 ipv4.addresses $MY_IP/$MY_PREFIX +nmcli con mod br0 ipv4.gateway $MY_GATEWAY +nmcli con mod br0 ipv4.method manual +nmcli con up br0 +nmcli con add con-name br0-slave0 ifname "$DEFAULT_DEV" type bridge-slave master br0 +nmcli con up br0-slave0 +END +``` + +> NOTE: The last set of commands above is wrapped in a “nohup” script because it will disable networking temporarily. The nohup command should allow the nmcli commands to finish running even while your ssh connection is down. Beware that it may take 10 or so seconds for the connection to come back up and that you will have to start a new ssh connection if you changed the server’s IP address. +> +> NOTE: The above network configuration creates a [network bridge][5] on top of the default connection so that we can run a virtual machine instance directly on the server for testing later. If you do not want to test the netboot image directly on the server, you can skip creating the bridge and set the static IP address directly on your default network connection. + +### Install and Configure NFS4 + +Start by installing the nfs-utils package: + +``` +$ dnf install -y nfs-utils +``` + +Create a top-level [pseudo filesystem][6] for the NFS exports and share it out to your network: + +``` +$ MY_SUBNET=192.0.2.0 +$ mkdir /export +$ echo "/export -fsid=0,ro,sec=sys,root_squash $MY_SUBNET/$MY_PREFIX" > /etc/exports +``` + +SELinux will interfere with the netboot server’s operation. Configuring exceptions for it is beyond the scope of this tutorial, so we will disable it: + +``` +$ sed -i '/GRUB_CMDLINE_LINUX/s/"$/ audit=0 selinux=0"/' /etc/default/grub +$ grub2-mkconfig -o /boot/grub2/grub.cfg +$ sed -i 's/SELINUX=enforcing/SELINUX=disabled/' /etc/sysconfig/selinux +$ setenforce 0 +``` + +> NOTE: Editing the grub command line should not be necessary, but simply editing /etc/sysconfig/selinux proved ineffective across reboots of Fedora Server 28 during testing, so the “selinux=0” flag has been set here to be doubly sure. + +Now, add an exception for the NFS service to the local firewall and start the NFS service: + +``` +$ firewall-cmd --add-service nfs +$ firewall-cmd --runtime-to-permanent +$ systemctl enable nfs-server.service +$ systemctl start nfs-server.service +``` + +### Create the Netboot Image + +Now that our NFS server is up and running, we need to supply it with an operating system image to serve to the client computers. We will start with a very minimal image and add to it after everything is working. + +First, create a new directory where our image will be stored: + +``` +$ mkdir /fc28 +``` + +Use the “dnf” command to build the image under the new directory with only a few base packages: + +``` +$ dnf -y --releasever=28 --installroot=/fc28 install fedora-release systemd passwd rootfiles sudo dracut dracut-network nfs-utils vim-minimal dnf +``` + +It is important that the “kernel” packages were omitted from the above command. Before they are installed, we need to tweak the set of drivers that will be included in the “initramfs” image that is built automatically when the kernel is first installed. In particular, we need to disable “hostonly” mode so that the initramfs image will work on a wider set of hardware platforms and we need to add support for networking and NFS: + +``` +$ echo 'hostonly=no' > /fc28/etc/dracut.conf.d/hostonly.conf +$ echo 'add_dracutmodules+=" network nfs "' > /fc28/etc/dracut.conf.d/netboot.conf +``` + +Now, install the kernel: + +``` +$ dnf -y --installroot=/fc28 install kernel +``` + +Set a rule to prevent the kernel from being updated: + +``` +$ echo 'exclude=kernel-*' >> /fc28/etc/dnf/dnf.conf +``` + +Set the locale: + +``` +$ echo 'LANG="en_US.UTF-8"' > /fc28/etc/locale.conf +``` + +> NOTE: Some programs (e.g. GNOME Terminal) will not function if the locale is not properly configured. + +Blank root’s passwd: + +``` +$ sed -i 's/^root:\*/root:/' /fc28/etc/shadow +``` + +Set the client’s hostname: + +``` +$ MY_CLIENT_HOSTNAME=client-01.example.edu +$ echo $MY_CLIENT_HOSTNAME > /fc28/etc/hostname +``` + +Disable logging to the console: + +``` +$ echo 'kernel.printk = 0 4 1 7' > /fc28/etc/sysctl.d/00-printk.conf +``` + +Define a local “liveuser” in the netboot image: + +``` +$ echo 'liveuser:x:1000:1000::/home/liveuser:/bin/bash' >> /fc28/etc/passwd +$ echo 'liveuser::::::::' >> /fc28/etc/shadow +$ echo 'liveuser:x:1000:' >> /fc28/etc/group +$ echo 'liveuser:!::' >> /fc28/etc/gshadow +``` + +Allow “liveuser” to sudo: + +``` +$ echo 'liveuser ALL=(ALL) NOPASSWD: ALL' > /fc28/etc/sudoers.d/liveuser +``` + +Enable automatic home directory creation: + +``` +$ dnf install -y --installroot=/fc28 authselect oddjob-mkhomedir +$ echo 'dirs /home' > /fc28/etc/rwtab.d/home +$ chroot /fc28 authselect select sssd with-mkhomedir --force +$ chroot /fc28 systemctl enable oddjobd.service +``` + +Since multiple clients will be mounting our image concurrently, we need to configure the image so that it will operate in read-only mode: + +``` +$ sed -i 's/^READONLY=no$/READONLY=yes/' /fc28/etc/sysconfig/readonly-root +``` + +Configure logging to go to RAM rather than permanent storage: + +``` +$ sed -i 's/^#Storage=auto$/Storage=volatile/' /fc28/etc/systemd/journald.conf +``` + +Configure DNS: + +``` +$ MY_DNS1=192.0.2.91 +$ MY_DNS2=192.0.2.92 +$ cat << END > /fc28/etc/resolv.conf +nameserver $MY_DNS1 +nameserver $MY_DNS2 +END +``` + +Work-around a few bugs that exist for read-only root mounts at the time this tutorial is being written ([BZ1542567][7]): + +``` +$ echo 'dirs /var/lib/gssproxy' > /fc28/etc/rwtab.d/gssproxy +$ cat << END > /fc28/etc/rwtab.d/systemd +dirs /var/lib/systemd/catalog +dirs /var/lib/systemd/coredump +END +``` + +Finally, we can create the NFS filesystem for our image and share it out to our subnet: + +``` +$ mkdir /export/fc28 +$ echo '/fc28 /export/fc28 none bind 0 0' >> /etc/fstab +$ mount /export/fc28 +$ echo "/export/fc28 -ro,sec=sys,no_root_squash $MY_SUBNET/$MY_PREFIX" > /etc/exports.d/fc28.exports +$ exportfs -vr +``` + +### Create the Boot Loader + +Now that we have an operating system available to netboot, we need a boot loader to kickstart it on the client systems. For this setup, we will be using [iPXE][8]. + +> NOTE: This section and the following section — Testing with QEMU — can be done on a separate computer; they do not have to be run on the netboot server. + +Install git and use it to download iPXE: + +``` +$ dnf install -y git +$ git clone http://git.ipxe.org/ipxe.git $HOME/ipxe +``` + +Now we need to create a special startup script for our bootloader: + +``` +$ cat << 'END' > $HOME/ipxe/init.ipxe +#!ipxe + +prompt --key 0x02 --timeout 2000 Press Ctrl-B for the iPXE command line... && shell || + +dhcp || exit +set prefix file:///linux +chain ${prefix}/boot.cfg || exit +END +``` + +Enable the “file” download protocol: + +``` +$ echo '#define DOWNLOAD_PROTO_FILE' > $HOME/ipxe/src/config/local/general.h +``` + +Install the C compiler and related tools and libraries: + +``` +$ dnf groupinstall -y "C Development Tools and Libraries" +``` + +Build the boot loader: + +``` +$ cd $HOME/ipxe/src +$ make clean +$ make bin-x86_64-efi/ipxe.efi EMBED=../init.ipxe +``` + +Make note of where the where the newly-compiled boot loader is. We will need it for the next section: + +``` +$ IPXE_FILE="$HOME/ipxe/src/bin-x86_64-efi/ipxe.efi" +``` + +### Testing with QEMU + +This section is optional, but you will need to duplicate the file layout of the [EFI system partition][9] that is shown below on your physical machines to configure them for netbooting. + +> NOTE: You could also copy the files to a TFTP server and reference that server from DHCP if you wanted a fully diskless system. + +In order to test our boot loader with QEMU, we are going to create a small disk image containing only an EFI system partition and our startup files. + +Start by creating the required directory layout for the EFI system partition and copying the boot loader that we created in the previous section to it: + +``` +$ mkdir -p $HOME/esp/efi/boot +$ mkdir $HOME/esp/linux +$ cp $IPXE_FILE $HOME/esp/efi/boot/bootx64.efi +``` + +The below command should identify the kernel version that our netboot image is using and store it in a variable for use in the remaining configuration directives: + +``` +$ DEFAULT_VER=$(ls -c /fc28/lib/modules | head -n 1) +``` + +Define the boot configuration that our client computers will be using: + +``` +$ MY_DNS1=192.0.2.91 +$ MY_DNS2=192.0.2.92 +$ MY_NFS4=server-01.example.edu +$ cat << END > $HOME/esp/linux/boot.cfg +#!ipxe + +kernel --name kernel.efi \${prefix}/vmlinuz-$DEFAULT_VER initrd=initrd.img ro ip=dhcp rd.peerdns=0 nameserver=$MY_DNS1 nameserver=$MY_DNS2 root=nfs4:$MY_NFS4:/fc28 console=tty0 console=ttyS0,115200n8 audit=0 selinux=0 quiet +initrd --name initrd.img \${prefix}/initramfs-$DEFAULT_VER.img +boot || exit +END +``` + +> NOTE: The above boot script shows a minimal example of how to get iPXE to netboot Linux. Much more complex configurations are possible. Most notably, iPXE has support for interactive boot menus which can be configured with a default selection and a timeout. A more advanced iPXE script could, for example, default to booting an operation system from the local disk and only go to the netboot operation if a user pressed a key before a countdown timer reached zero. + +Copy the Linux kernel and its associated initramfs to the EFI system partition: + +``` +$ cp $(find /fc28/lib/modules -maxdepth 2 -name 'vmlinuz' | grep -m 1 $DEFAULT_VER) $HOME/esp/linux/vmlinuz-$DEFAULT_VER +$ cp $(find /fc28/boot -name 'init*' | grep -m 1 $DEFAULT_VER) $HOME/esp/linux/initramfs-$DEFAULT_VER.img +``` + +Our resulting directory layout should look like this: + +``` +esp +├── efi +│ └── boot +│ └── bootx64.efi +└── linux + ├── boot.cfg + ├── initramfs-4.18.18-200.fc28.x86_64.img + └── vmlinuz-4.18.18-200.fc28.x86_64 +``` + +To use our EFI system partition with QEMU, we need to create a small “uefi.img” disk image containing it and then connect that to QEMU as the primary boot drive. + +Begin by installing the necessary tools: + +``` +$ dnf install -y parted dosfstools +``` + +Now create the “uefi.img” file and copy the files from the “esp” directory into it: + +``` +$ ESP_SIZE=$(du -ks $HOME/esp | cut -f 1) +$ dd if=/dev/zero of=$HOME/uefi.img count=$((${ESP_SIZE}+5000)) bs=1KiB +$ UEFI_DEV=$(losetup --show -f $HOME/uefi.img) +$ parted ${UEFI_DEV} -s mklabel gpt mkpart EFI FAT16 1MiB 100% toggle 1 boot +$ mkfs -t msdos ${UEFI_DEV}p1 +$ mkdir -p $HOME/mnt +$ mount ${UEFI_DEV}p1 $HOME/mnt +$ cp -r $HOME/esp/* $HOME/mnt +$ umount $HOME/mnt +$ losetup -d ${UEFI_DEV} +``` + +> NOTE: On a physical computer, you need only copy the files from the “esp” directory to the computer’s existing EFI system partition. You do not need the “uefi.img” file to boot a physical computer. +> +> NOTE: On a physical computer you can rename the “bootx64.efi” file if a file by that name already exists, but if you do so, you will probably have to edit the computer’s BIOS settings and add the renamed efi file to the boot list. + +Next we need to install the qemu package: + +``` +$ dnf install -y qemu-system-x86 +``` + +Allow QEMU to access the bridge that we created in the “Initial Configuration” section of this tutorial: + +``` +$ echo 'allow br0' > /etc/qemu/bridge.conf +``` + +Create a copy of the “OVMF_VARS.fd” image to store our virtual machine’s persistent BIOS settings: + +``` +$ cp /usr/share/edk2/ovmf/OVMF_VARS.fd $HOME +``` + +Now, start the virtual machine: + +``` +$ qemu-system-x86_64 -machine accel=kvm -nographic -m 1024 -drive if=pflash,format=raw,unit=0,file=/usr/share/edk2/ovmf/OVMF_CODE.fd,readonly=on -drive if=pflash,format=raw,unit=1,file=$HOME/OVMF_VARS.fd -drive if=ide,format=raw,file=$HOME/uefi.img -net bridge,br=br0 -net nic,model=virtio +``` + +If all goes well, you should see results similar to what is shown in the below image: + +![][10] +You can use the “shutdown” command to get out of the virtual machine and back to the server: + +``` +$ sudo shutdown -h now +``` + +> NOTE: If something goes wrong and the virtual machine hangs, you may need to start a new ssh session to the server and use the “kill” command to terminate the “qemu-system-x86_64” process. + +### Adding to the Image + +Adding to the image should be a simple matter of chroot’ing into the image on the server and running “dnf install ”. + +There is no limit to what can be installed on the netboot image. A full graphical installation should function perfectly. + +Here is an example of how to bring our minimal netboot image up to a complete graphical installation: + +``` +$ for i in dev dev/pts dev/shm proc sys run; do mount -o bind /$i /fc28/$i; done +$ chroot /fc28 /usr/bin/bash --login +$ dnf -y groupinstall "Fedora Workstation" +$ dnf -y remove gnome-initial-setup +$ systemctl disable sshd.service +$ systemctl enable gdm.service +$ systemctl set-default graphical.target +$ sed -i 's/SELINUX=enforcing/SELINUX=disabled/' /etc/sysconfig/selinux +$ logout +$ for i in run sys proc dev/shm dev/pts dev; do umount /fc28/$i; done +``` + +Optionally, you may want to enable automatic login for the “liveuser” account: + +``` +$ sed -i '/daemon/a AutomaticLoginEnable=true' /fc28/etc/gdm/custom.conf +$ sed -i '/daemon/a AutomaticLogin=liveuser' /fc28/etc/gdm/custom.conf +``` + + +-------------------------------------------------------------------------------- + +via: https://fedoramagazine.org/how-to-build-a-netboot-server-part-1/ + +作者：[Gregory Bartholomew][a] +选题：[lujun9972][b] +译者：[译者ID](https://github.com/译者ID) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]: https://fedoramagazine.org/author/glb/ +[b]: https://github.com/lujun9972 +[1]: https://en.wikipedia.org/wiki/Network_booting +[2]: https://dl.fedoraproject.org/pub/fedora/linux/releases/28/Server/x86_64/iso/ +[3]: https://fedoramagazine.org/wp-content/uploads/2018/11/installation-summary-1024x768.png +[4]: https://docs.fedoraproject.org/en-US/Fedora/25/html/Networking_Guide/ch-Configure_Host_Names.html#sec_Understanding_Host_Names +[5]: https://en.wikipedia.org/wiki/Bridging_(networking) +[6]: https://www.centos.org/docs/5/html/5.1/Deployment_Guide/s3-nfs-server-config-exportfs-nfsv4.html +[7]: https://bugzilla.redhat.com/show_bug.cgi?id=1542567 +[8]: https://ipxe.org/ +[9]: https://en.wikipedia.org/wiki/EFI_system_partition +[10]: https://fedoramagazine.org/wp-content/uploads/2018/11/netboot-liveuser-1024x641.png diff --git a/sources/tech/20181123 Three SSH GUI Tools for Linux.md b/sources/tech/20181123 Three SSH GUI Tools for Linux.md new file mode 100644 index 0000000000..9691a737ca --- /dev/null +++ b/sources/tech/20181123 Three SSH GUI Tools for Linux.md @@ -0,0 +1,176 @@ +[#]: collector: (lujun9972) +[#]: translator: ( ) +[#]: reviewer: ( ) +[#]: publisher: ( ) +[#]: subject: (Three SSH GUI Tools for Linux) +[#]: via: (https://www.linux.com/blog/learn/intro-to-linux/2018/11/three-ssh-guis-linux) +[#]: author: (Jack Wallen https://www.linux.com/users/jlwallen) +[#]: url: ( ) + +Three SSH GUI Tools for Linux +====== + + + +At some point in your career as a Linux administrator, you’re going to use Secure Shell (SSH) to remote into a Linux server or desktop. Chances are, you already have. In some instances, you’ll be SSH’ing into multiple Linux servers at once. In fact, Secure Shell might well be one of the most-used tools in your Linux toolbox. Because of this, you’ll want to make the experience as efficient as possible. For many admins, nothing is as efficient as the command line. However, there are users out there who do prefer a GUI tool, especially when working from a desktop machine to remote into and work on a server. + +If you happen to prefer a good GUI tool, you’ll be happy to know there are a couple of outstanding graphical tools for SSH on Linux. Couple that with a unique terminal window that allows you to remote into multiple machines from the same window, and you have everything you need to work efficiently. Let’s take a look at these three tools and find out if one (or more) of them is perfectly apt to meet your needs. + +I’ll be demonstrating these tools on [Elementary OS][1], but they are all available for most major distributions. + +### PuTTY + +Anyone that’s been around long enough knows about [PuTTY][2]. In fact, PuTTY is the de facto standard tool for connecting, via SSH, to Linux servers from the Windows environment. But PuTTY isn’t just for Windows. In fact, from withing the standard repositories, PuTTY can also be installed on Linux. PuTTY’s feature list includes: + + * Saved sessions. + + * Connect via IP address or hostname. + + * Define alternative SSH port. + + * Connection type definition. + + * Logging. + + * Options for keyboard, bell, appearance, connection, and more. + + * Local and remote tunnel configuration + + * Proxy support + + * X11 tunneling support + + + + +The PuTTY GUI is mostly a way to save SSH sessions, so it’s easier to manage all of those various Linux servers and desktops you need to constantly remote into and out of. Once you’ve connected, from PuTTY to the Linux server, you will have a terminal window in which to work. At this point, you may be asking yourself, why not just work from the terminal window? For some, the convenience of saving sessions does make PuTTY worth using. + +Installing PuTTY on Linux is simple. For example, you could issue the command on a Debian-based distribution: + +``` +sudo apt-get install -y putty +``` + +Once installed, you can either run the PuTTY GUI from your desktop menu or issue the command putty. In the PuTTY Configuration window (Figure 1), type the hostname or IP address in the HostName (or IP address) section, configure the port (if not the default 22), select SSH from the connection type, and click Open. + +![PuTTY Connection][4] + +Figure 1: The PuTTY Connection Configuration Window. + +[Used with permission][5] + +Once the connection is made, you’ll then be prompted for the user credentials on the remote server (Figure 2). + +![log in][7] + +Figure 2: Logging into a remote server with PuTTY. + +[Used with permission][5] + +To save a session (so you don’t have to always type the remote server information), fill out the IP address (or hostname), configure the port and connection type, and then (before you click Open), type a name for the connection in the top text area of the Saved Sessions section, and click Save. This will then save the configuration for the session. To then connect to a saved session, select it from the saved sessions window, click Load, and then click Open. You should then be prompted for the remote credentials on the remote server. + +### EasySSH + +Although [EasySSH][8] doesn’t offer the amount of configuration options found in PuTTY, it’s (as the name implies) incredibly easy to use. One of the best features of EasySSH is that it offers a tabbed interface, so you can have multiple SSH connections open and quickly switch between them. Other EasySSH features include: + + * Groups (so you can group tabs for an even more efficient experience). + + * Username/password save. + + * Appearance options. + + * Local and remote tunnel support. + + + + +Install EasySSH on a Linux desktop is simple, as the app can be installed via flatpak (which does mean you must have Flatpak installed on your system). Once flatpak is installed, add EasySSH with the commands: + +``` +sudo flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo + +sudo flatpak install flathub com.github.muriloventuroso.easyssh +``` + +Run EasySSH with the command: + +``` +flatpak run com.github.muriloventuroso.easyssh +``` + +The EasySSH app will open, where you can click the + button in the upper left corner. In the resulting window (Figure 3), configure your SSH connection as required. + +![Adding a connection][10] + +Figure 3: Adding a connection in EasySSH is simple. + +[Used with permission][5] + +Once you’ve added the connection, it will appear in the left navigation of the main window (Figure 4). + +![EasySSH][12] + +Figure 4: The EasySSH main window. + +[Used with permission][5] + +To connect to a remote server in EasySSH, select it from the left navigation and then click the Connect button (Figure 5). + +![Connecting][14] + +Figure 5: Connecting to a remote server with EasySSH. + +[Used with permission][5] + +The one caveat with EasySSH is that you must save the username and password in the connection configuration (otherwise the connection will fail). This means anyone with access to the desktop running EasySSH can remote into your servers without knowing the passwords. Because of this, you must always remember to lock your desktop screen any time you are away (and make sure to use a strong password). The last thing you want is to have a server vulnerable to unwanted logins. + +### Terminator + +Terminator is not actually an SSH GUI. Instead, Terminator functions as a single window that allows you to run multiple terminals (and even groups of terminals) at once. Effectively you can open Terminator, split the window vertical and horizontally (until you have all the terminals you want), and then connect to all of your remote Linux servers by way of the standard SSH command (Figure 6). + +![Terminator][16] + +Figure 6: Terminator split into three different windows, each connecting to a different Linux server. + +[Used with permission][5] + +To install Terminator, issue a command like: + +### sudo apt-get install -y terminator + +Once installed, open the tool either from your desktop menu or from the command terminator. With the window opened, you can right-click inside Terminator and select either Split Horizontally or Split Vertically. Continue splitting the terminal until you have exactly the number of terminals you need, and then start remoting into those servers. +The caveat to using Terminator is that it is not a standard SSH GUI tool, in that it won’t save your sessions or give you quick access to those servers. In other words, you will always have to manually log into your remote Linux servers. However, being able to see your remote Secure Shell sessions side by side does make administering multiple remote machines quite a bit easier. + +Few (But Worthwhile) Options + +There aren’t a lot of SSH GUI tools available for Linux. Why? Because most administrators prefer to simply open a terminal window and use the standard command-line tools to remotely access their servers. However, if you have a need for a GUI tool, you have two solid options and one terminal that makes logging into multiple machines slightly easier. Although there are only a few options for those looking for an SSH GUI tool, those that are available are certainly worth your time. Give one of these a try and see for yourself. + +-------------------------------------------------------------------------------- + +via: https://www.linux.com/blog/learn/intro-to-linux/2018/11/three-ssh-guis-linux + +作者：[Jack Wallen][a] +选题：[lujun9972][b] +译者：[译者ID](https://github.com/译者ID) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]: https://www.linux.com/users/jlwallen +[b]: https://github.com/lujun9972 +[1]: https://elementary.io/ +[2]: https://www.chiark.greenend.org.uk/~sgtatham/putty/latest.html +[3]: https://www.linux.com/files/images/sshguis1jpg +[4]: https://www.linux.com/sites/lcom/files/styles/rendered_file/public/ssh_guis_1.jpg?itok=DiNTz_wO (PuTTY Connection) +[5]: https://www.linux.com/licenses/category/used-permission +[6]: https://www.linux.com/files/images/sshguis2jpg +[7]: https://www.linux.com/sites/lcom/files/styles/rendered_file/public/ssh_guis_2.jpg?itok=4ORsJlz3 (log in) +[8]: https://github.com/muriloventuroso/easyssh +[9]: https://www.linux.com/files/images/sshguis3jpg +[10]: https://www.linux.com/sites/lcom/files/styles/rendered_file/public/ssh_guis_3.jpg?itok=bHC2zlda (Adding a connection) +[11]: https://www.linux.com/files/images/sshguis4jpg +[12]: https://www.linux.com/sites/lcom/files/styles/rendered_file/public/ssh_guis_4.jpg?itok=hhJzhRIg (EasySSH) +[13]: https://www.linux.com/files/images/sshguis5jpg +[14]: https://www.linux.com/sites/lcom/files/styles/rendered_file/public/ssh_guis_5.jpg?itok=piFEFYTQ (Connecting) +[15]: https://www.linux.com/files/images/sshguis6jpg +[16]: https://www.linux.com/sites/lcom/files/styles/rendered_file/public/ssh_guis_6.jpg?itok=-kYl6iSE (Terminator) diff --git a/sources/tech/20181124 14 Best ASCII Games for Linux That are Insanely Good.md b/sources/tech/20181124 14 Best ASCII Games for Linux That are Insanely Good.md new file mode 100644 index 0000000000..094467698b --- /dev/null +++ b/sources/tech/20181124 14 Best ASCII Games for Linux That are Insanely Good.md @@ -0,0 +1,335 @@ +[#]: collector: (lujun9972) +[#]: translator: ( ) +[#]: reviewer: ( ) +[#]: publisher: ( ) +[#]: subject: (14 Best ASCII Games for Linux That are Insanely Good) +[#]: via: (https://itsfoss.com/best-ascii-games/) +[#]: author: (Ankush Das https://itsfoss.com/author/ankush/) +[#]: url: ( ) + +14 Best ASCII Games for Linux That are Insanely Good +====== + +Text-based or should I say [terminal-based games][1] were very popular a decade back – when you didn’t have visual masterpieces like God Of War, Red Dead Redemption 2 or Spiderman. + +Of course, the Linux platform has its share of good games – but not always the “latest and greatest”. But, there are some ASCII games out there – to which you can never turn your back on. + +I’m not sure if you’d believe me, some of the ASCII games proved to be very addictive (So, it might take a while for me to resume work on the next article, or I might just get fired? – Help me!) + +Jokes apart, let us take a look at the best ASCII games. + +**Note:** Installing ASCII games could be time-consuming (some might ask you to install additional dependencies or simply won’t work). You might even encounter some ASCII games that require you build from Source. So, we’ve filtered out only the ones that are easy to install/run – without breaking a sweat. + +### Things to do before Running or Installing an ASCII Game + +Some of the ASCII games might require you to install [Simple DirectMedia Layer][2] unless you already have it installed. So, in case, you should install them first before trying to run any of the games mentioned in this article. + +For that, you just need to type in these commands: + +``` +sudo apt install libsdl2-2.0 +``` + +``` +sudo apt install libsdl2_mixer-2.0 +``` + \--args**) over and over. You can document it with a custom domain, adding directives and indexes along the way. + +Here's an example from our **recipe** domain: + +``` +The recipe contains `tomato` and `cilantro`. + +.. rcp:recipe:: TomatoSoup + :contains: tomato cilantro salt pepper + + This recipe is a tasty tomato soup, combine all ingredients + and cook. +``` + +Now that we've defined the recipe **TomatoSoup** , we can reference it anywhere in our documentation using the custom role **refef**. For example: + +``` +You can use the :rcp:reref:`TomatoSoup` recipe to feed your family. +``` + +This enables our recipes to show up in two indices: the first lists all recipes, and the second lists all recipes by ingredient. + +### What's in a domain? + +A Sphinx domain is a specialized container that ties together roles, directives, and indices, among other things. The domain has a name ( **rcp** ) to address its components in the documentation source. It announces its existence to Sphinx in the **setup()** method of the package. From there, Sphinx can find roles and directives, since these are part of the domain. + +This domain also serves as the central catalog of objects in this sample. Using initial data, it defines two variables, **objects** and **obj2ingredient**. These contain a list of all objects defined (all recipes) and a hash that maps a canonical ingredient name to the list of objects. + +``` +initial_data = { + 'objects': [], # object list + 'obj2ingredient': {}, # ingredient -> [objects] +} +``` + +The way we name objects is common across our extension. For each object created, the canonical name is **rcp. . **, where **< typename>** is the Python type of the object, and **< objectname>** is the name the documentation writer gives the object. This enables the extension to use different object types that share the same name. + +Having a canonical name and central place for our objects is a huge advantage. Both our indices and our cross-referencing code use this feature. + +### Custom roles and directives + +In our example, **.. rcp:recipe::** indicates a custom directive. You might think it's overly specific to create custom syntax for these items, but it illustrates the degree of customization you can get in Sphinx. This provides rich markup that structures documents and leads to better docs. Specialization allows us to extract information from our docs. + +Our definition for this directive will provide minimal formatting, but it will be functional. + +``` +class RecipeNode(ObjectDescription): + """A custom node that describes a recipe.""" + + required_arguments = 1 + + option_spec = { + 'contains': rst.directives.unchanged_required + } +``` + +For this directive, **required_arguments** tells Sphinx to expect one parameter, the recipe name. **option_spec** lists the optional arguments, including their names. Finally, **has_content** specifies that there will be more reStructured Text as a child to this node. + +We also implement multiple methods: + + * **handle_signature()** implements parsing the signature of the directive and passes on the object's name and type to its superclass + * **add_taget_and_index()** adds a target (to link to) and an entry to the index for this node + + + +### Creating indices + +Both **IngredientIndex** and **RecipeIndex** are derived from Sphinx's **Index** class. They implement custom logic to generate a tuple of values that define the index. Note that **RecipeIndex** is a degenerate index that has only one entry. Extending it to cover more object types—and moving from a **RecipeDomain** to a **CookbookDomain** —is not yet part of the code. + +Both indices use the method **generate()** to do their work. This method combines the information from our domain, sorts it, and returns it in a list structure that will be accepted by Sphinx. See the [Sphinx Domain API][3] page for more information. + +The first time you visit the Domain API page, you may be a little overwhelmed by the structure. But our ingredient index is just a list of tuples, like **('tomato', 'TomatoSoup', 'test', 'rec-TomatoSoup',...)**. + +### Referencing recipes + +Adding cross-references is not difficult (but it's also not a given). Add an **XRefRole** to the domain and implement the method **resolve_xref()**. Having a custom role to reference a type allows us to unambiguously reference any object, even if two objects have the same name. If you look at the parameters of **resolve_xref()** in **Domain** , you'll see **typ** and **target**. These define the cross-reference type and its target name. We'll use **target** to resolve our destination from our domain's **objects** because we currently have only one type of node. + +We can add the cross-reference role to **RecipeDomain** in the following way: + +``` +roles = { + 'reref': XRefRole() +} +``` + +There's nothing for us to implement. Defining a working **resolve_xref()** and attaching an **XRefRole** to the domain is all you need to do. + + +-------------------------------------------------------------------------------- + +via: https://opensource.com/article/18/11/building-custom-workflows-sphinx + +作者：[Mark Meyer][a] +选题：[lujun9972][b] +译者：[译者ID](https://github.com/译者ID) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]: https://opensource.com/users/ofosos +[b]: https://github.com/lujun9972 +[1]: http://www.sphinx-doc.org/en/master/ +[2]: https://github.com/ofosos/sphinxrecipes +[3]: https://www.sphinx-doc.org/en/master/extdev/domainapi.html#sphinx.domains.Index.generate diff --git a/sources/tech/20181128 How to test your network with PerfSONAR.md b/sources/tech/20181128 How to test your network with PerfSONAR.md new file mode 100644 index 0000000000..9e9e66ef62 --- /dev/null +++ b/sources/tech/20181128 How to test your network with PerfSONAR.md @@ -0,0 +1,148 @@ +[#]: collector: (lujun9972) +[#]: translator: ( ) +[#]: reviewer: ( ) +[#]: publisher: ( ) +[#]: subject: (How to test your network with PerfSONAR) +[#]: via: (https://opensource.com/article/18/11/how-test-your-network-perfsonar) +[#]: author: (Jessica Repka https://opensource.com/users/jrepka) +[#]: url: ( ) + +How to test your network with PerfSONAR +====== +Set up a single-node configuration to measure your network performance. + + +[PerfSONAR][1] is a network measurement toolkit collection for testing and sharing data on end-to-end network perfomance. + +The overall benefit of using network measurement tools like PerfSONAR is they can find issues before they become a large elephant in the room that nobody wants to talk about. Specifically, with the right answers from the right tools, patching can become more stringent, network traffic can be shaped to speed connections across the board, and the network infrastructure design can be improved. + +PerfSONAR is licensed under the open source Apache 2.0 license, which makes it more affordable than most tools that do this type of analysis, a key advantage given constrained network infrastructure budgets. + +### PerfSONAR versions + +Several versions of PerfSONAR are available: + + * **Perfsonar-tools:** The command line client version meant for on-demand testing. + * **Perfsonar-testpoint:** Adds automated testing and central management testing to PerfSONAR-tools. It has an archiving feature, but the archive must be set to an external node. + * **Perfsonar-core:** Includes everything in the testpoint software, but with local rather than external archiving. + * **Perfsonar-toolkit:** The core software; it includes a web UI with systemwide security settings. + * **Perfsonar-centralmanagement:** A completely separate version of PerfSONAR that uses mass grids of nodes to display results. It also has a feature to push out task templates to every node that is sending measurements back to the central host. + + + +This tutorial will use **PerfSonar-toolkit** ; the tools used in this software include [iPerf, iPerf3][2], and [OWAMP][3]. + +### Requirements + + * **Recommended operating system:** CentOS/RHEL7 + * **ISO:** [Downloading][4] the full installation ISO is the fastest way to get the software up and running. While there is a [Debian version][5], it is much harder and more complicated to use. + * **Minimum hardware requirements:** 2 cores and 4GB RAM + * **Recommended hardware:** 200GB HDD, 4 cores, 6GB of RAM + + + +### Installing and configuring PerfSONAR + +The installation is a quick CentOS install where you pick your timezone and configuration for the hard drive and user. I suggest using hard drive autoconfiguration, as you only need to choose "Install Toolkit" and follow the prompts from there. + +Select your language. + +Select a destination. + +After base installation, you see the Linux login screen. + +After you log in, you are prompted to create a user ID and password to log into PerfSONAR's web frontend—make sure to remember your login information. + +You're also asked to disable SSH access for root and create a new user for sudo; just follow the steps to create the new user. + +You can use a provisioning service to automatically provide an IP address and hostname. Otherwise, you will have to set the hostname (optional) and configure the IP address. + +### Log into the web frontend + +Once the base configuration is complete, you can log into the web frontend via ** +``` + +Change the Output Refresh Interval: + +``` +$ htop -d 10 +``` + +As you can see, htop usage is incredibly easier than the usage of top command. + +Refer htop man pages to know more about the available options and functionalities. + +``` +$ man htop +``` + +Also, refer the project home page and HitHub repository. + ++ [htop website](http://hisham.hm/htop/) ++ [htop GitHub Repository](https://github.com/hishamhm/htop) + +#### 2\. Vtop + +**Vtop** is yet another alternative to good-old top utility. It is a free and open source, command-line system activity monitor written in **NodeJS** and released under MIT. It uses unicode braille characters to draw CPU and Memory charts, helping you to visualize spikes. + +Make sure you have NodeJS installed on your system. If not installed yet, refer the following guide. + +Once node installed, run the following command to install Vtop. + +``` +$ npm install -g vtop +``` + +After installing Vtop, simply run vtop to start monitoring. + +``` +$ vtop +``` + +Sample output: + +![][3] + +As you can see, Vtop interface is little bit different than top and htop programs. It displays each details in a separate box layout. You will see all shortcuts keys to interact with Vtop at the bottom. + +Here is the list of shortcuts: + + * **dd** – Kill the processes. + * **UP** arrow or **k** – Move up. + * **DOWN** arrow or **j** – Move down. + * **Left** arrow or or **h** to – Zoom the graphs in. + * **Right** arrow or **l** – Zoom the graphs out. + * **g** – Jump to top of the process list. + * **SHIFT+g** – Jump to end of the process list. + * **c** – Sort processes by CPU usage. + * **m** – Sort processes by memory usage. + + + +For more details, refer the following Vtop resources. + ++ [Vtop website](http://parall.ax/vtop) ++ [Vtop GitHub Repository](https://github.com/MrRio/vtop) + + +#### 3\. Gtop + +Gtop is same as Vtop system activity monitor. It is also written in NodeJS and released under MIT license. + +To install it, run: + +``` +$ npm install gtop -g +``` + +Start gtop using command: + +``` +$ gtop +``` + +Sample output: + + + +I noticed Gtop interface is very nice. It showed each elements with different set of colors which is eye-pleasing. + +Keyboard shortcuts: + + * **p** – Sort processes by process Id. + * **c** – Sort processes by CPU usage. + * **m** – Sort processes by Memory usage. + * **q** or **ctrl+c** – Quit Gtop. + + + +For more details, visit Gtop GitHub page. + ++ [Gtop GitHub Repository](https://github.com/aksakalli/gtop) + + +#### 4\. Gotop + +As the name says, **Gotop** is a TUI graphical activity monitor, written in **Go** programming language. It is completely free, open source and inspired by **gtop** and **vtop** programs which we mentioned in the previous sections. We already have written about it a while ago. If you’re interested to learn about it, please visit the following link. + ++ [Gotop – Yet Another TUI Graphical Activity Monitor, Written In Go +](https://www.ostechnix.com/manage-python-packages-using-pip/) + +#### 5\. Ptop + +Some of you might not like programs written in NodeJS and Go. If you’re one of them, there is another process monitor program named **Ptop** , which is written in **Python** programming language. It is free, open source system activity monitor, released under MIT license. + +Ptop is compatible with both Python2.x and Python3.x, so you can easily install it using **Pip** , a package manager to install programs developed in Python. If you haven’t installed Pip yet, refer the following link. + ++ [How To Manage Python Packages Using Pip](https://www.ostechnix.com/manage-python-packages-using-pip/) + +After installing Pip, run the following command to install ptop. + +``` +$ pip install ptop +``` + +Or, you can compile from source as shown below. + +``` +$ git clone https://github.com/darxtrix/ptop +$ cd ptop/ +$ pip install -r requirements.txt # install requirements +$ sudo python setup.py install +``` + +To update Ptop, run: + +``` +$ pip install --upgrade ptop +``` + +Even if you don’t update, Ptop will prompt you if you’d like to update to the latest version when launch it for the first time. + +Now, let us run ptop and see what happens. + +``` +$ ptop +``` + +Here you go! + +Here is the list of shortcuts keys to interact with ptop: + + * **Ctrl+k** – Kill the process. + * **Ctrl+n** – Sort processes by memory usage. + * **Ctrl+t** – Sort processes by process lifetime. + * **Ctrl+r** – Reset the stats. + * **Ctrl+f** – Filter a specific process information. Just type process name and you will see its details only. + * **Ctrl+l** – View the information of a selected process. + * **g** – Go to the top of the process list. + * **Ctrl+q** – Quit Ptop. + + + +Ptop has a feature to change the theme. If you want a pretty output of Ptop, you could use any one of the available themes. Currently the following themes are supported: + + * colorful + * elegant + * simple + * dark + * light + + + +To set a theme, for example colorful, simply run: + +``` +$ ptop -t colorful +``` + +To view help section, use **-h** : + +``` +$ ptop -h +``` + +For more details, refer the project’s GitHub page. + ++ [Ptop Github Repository](https://github.com/darxtrix/ptop) + +#### 6\. Hegemon + +**Hegemon** is another system activity monitor application written in **Rust** programming language. If you’re fan of programs written in Rust, hegemon might be a good choice. We have published a brief review about Hegemon a while ago. Please visit the following link to know more about this tool. + +[Hegemon – A Modular System Monitor Application Written In Rust](https://www.ostechnix.com/hegemon-a-modular-system-monitor-application-written-in-rust/) + +### Conclusion + +You know now six alternatives to Top program. I won’t claim these programs are better than or best replacement for ‘top’ program. But it is always nice to know some alternatives. I use htop mostly to monitor the processes. Now is your turn. Have you used any tools listed here? Great! Which is your favorite tool and why? Please share your experience in the comment section below. + +More good stuffs to come. Stay tuned! + +Cheers! + + + +-------------------------------------------------------------------------------- + +via: https://www.ostechnix.com/some-alternatives-to-top-command-line-utility-you-might-want-to-know/ + +作者：[SK][a] +选题：[lujun9972][b] +译者：[译者ID](https://github.com/译者ID) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]: https://www.ostechnix.com/author/sk/ +[b]: https://github.com/lujun9972 +[1]: https://www.ostechnix.com/the-top-command-tutorial-with-examples-for-beginners/ +[2]: data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7 +[3]: http://www.ostechnix.com/wp-content/uploads/2018/11/vtop.png diff --git a/sources/tech/20181201 Boxing yourself in on the Linux command line.md b/sources/tech/20181201 Boxing yourself in on the Linux command line.md new file mode 100644 index 0000000000..a61ff6f2a4 --- /dev/null +++ b/sources/tech/20181201 Boxing yourself in on the Linux command line.md @@ -0,0 +1,125 @@ +[#]: collector: (lujun9972) +[#]: translator: ( ) +[#]: reviewer: ( ) +[#]: publisher: ( ) +[#]: subject: (Boxing yourself in on the Linux command line) +[#]: via: (https://opensource.com/article/18/12/linux-toy-boxes) +[#]: author: (Jason Baker https://opensource.com/users/jason-baker) +[#]: url: ( ) + +Boxing yourself in on the Linux command line +====== +Learn how to use the boxes utility to draw shapes with characters at the Linux terminal and make your words stand out. + + +It's the holiday season, and every Linux terminal user deserves a little gift. It doesn't matter whether you celebrate Christmas, another holiday, or nothing at all. So I'm gathering together a collection of 24 Linux command-line toys over the next few weeks for you to enjoy and share with your friends. Let's have a little fun and add a little joy to a month that, at least here in the northern hemisphere, can be a little bit cold and dreary. + +Chances are, there will be a few that you've heard of before. But, hopefully, we'll all have a chance to learn something new. (I know I did when doing some research to make sure I could make it to 24.) + +The first of our 24 Linux terminal toys is a program called boxes. Why start with boxes? Because it's going to be hard to wrap up all of our other command-line presents to you without it! + +On my Fedora machine, boxes wasn't installed by default, but it was in my normal repositories, so installing it was as simple as + +``` +$ sudo dnf install boxes -y +``` + +If you're on a different distribution, there's a good chance you'll find it in your default repositories as well. + +Boxes a utility I really wish I had in my high school and college computer science courses, where well-intentioned teachers insisted I provide very specific looking comment at the beginning of every source file, function, code block, etc. + +``` +/***************/ +/* Hello World */ +/***************/ +``` + +It turns out, once you add a few lines of text inside, formatting them can get, well, tedious. Enter boxes. Boxes is a simple utility for surrounding a block of text with an ASCII art-style box. It comes with defaults for source code commenting, as well as other options. + +It's really easy to use. Using pipes, I can push a short greeting into a box. + +``` +$ cat greeting.txt | boxes -d diamonds -a c +``` + +Which will give us the output as follows: + +``` + /\ /\ /\ + /\//\\/\ /\//\\/\ /\//\\/\ + /\//\\\///\\/\//\\\///\\/\//\\\///\\/\ +//\\\//\/\\///\\\//\/\\///\\\//\/\\///\\ +\\//\/ \/\\// + \/ \/ + /\ I'm wishing you all a /\ +//\\ joyous holiday season //\\ +\\// and a Happy Gnu Year! \\// + \/ \/ + /\ /\ +//\\/\ /\//\\ +\\///\\/\//\\\///\\/\//\\\///\\/\//\\\// + \/\\///\\\//\/\\///\\\//\/\\///\\\//\/ + \/\\//\/ \/\\//\/ \/\\//\/ + \/ \/ \/ +``` + +Or perhaps something more fun, like: + +``` +echo "I am a dog" | boxes -d dog -a c +``` + +Which will, unsurprisingly, give you the following: + +``` + __ _,--="=--,_ __ + / \." .-. "./ \ + / ,/ _ : : _ \/` \ + \ `| /o\ :_: /o\ |\__/ + `-'| :="~` _ `~"=: | + \` (_) `/ + .-"-. \ | / .-"-. +.---{ }--| /,.-'-.,\ |--{ }---. + ) (_)_)_) \_/`~-===-~`\_/ (_(_(_) ( +( I am a dog ) + ) ( +'---------------------------------------' +``` + +Boxes comes with [lots of options][1] for padding, position, and even processing regular expressions. You can learn more about boxes on the [project's homepage][2], or head over to [GitHub][3] to download the source code or contribute your own box. In fact, if you're looking for an idea to submit, I've got an idea for you: why not a holiday present? + +``` + _ _ + /_\/_\ + _______\_\/_/_______ +| ///\\\ | +| /// \\\ | +| | +| "Happy pull | +| request!" | +|____________________| +``` + +Boxes is open source under a GPLv2 license. + +Do you have a favorite command-line toy that you think I ought to profile? The calendar for this series is mostly filled out but I've got a few spots left. Let me know in the comments below, and I'll check it out. If there's space, I'll try to include it. If not, but I get some good submissions, I'll do a round-up of honorable mentions at the end. + +Or check out tomorrow's command-line toy, [Drive a locomotive through your Linux terminal][4]. + +-------------------------------------------------------------------------------- + +via: https://opensource.com/article/18/12/linux-toy-boxes + +作者：[Jason Baker][a] +选题：[lujun9972][b] +译者：[译者ID](https://github.com/译者ID) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]: https://opensource.com/users/jason-baker +[b]: https://github.com/lujun9972 +[1]: http://boxes.thomasjensen.com/examples.html +[2]: https://boxes.thomasjensen.com/ +[3]: https://github.com/ascii-boxes/boxes +[4]: https://opensource.com/article/18/12/linux-toy-sl diff --git a/sources/tech/20181202 Drive a locomotive through your Linux terminal.md b/sources/tech/20181202 Drive a locomotive through your Linux terminal.md new file mode 100644 index 0000000000..c600d4b522 --- /dev/null +++ b/sources/tech/20181202 Drive a locomotive through your Linux terminal.md @@ -0,0 +1,71 @@ +[#]: collector: (lujun9972) +[#]: translator: (geekpi) +[#]: reviewer: ( ) +[#]: publisher: ( ) +[#]: subject: (Drive a locomotive through your Linux terminal) +[#]: via: (https://opensource.com/article/18/12/linux-toy-sl) +[#]: author: (Jason Baker https://opensource.com/users/jason-baker) +[#]: url: ( ) + +Drive a locomotive through your Linux terminal +====== +Using the sl command, you can train yourself to get on track with a fun command-line experience. + + +It's December, and every Linux terminal user deserves a reward just for making through the year. So we're bringing you a sort of advent calendar of Linux command-line toys. What's a command-line toy? It might be a game, a pointless little time waster, or just something to bring you joy at the terminal. + +**sl** , which is short for steam locomotive. + +Today's Linux command-line toy is a suggestion from Opensource.com community moderator [Ben Cotton][1] . Ben suggested, which is short for steam locomotive. + +It's also, conveniently and not coincidentally, a common typo for the Linux **ls** command. Want to stop mistyping ls? Try installing **sl**. It's probably packaged for your default repos. For me, in Fedora, that means it was as simple to install as: + +``` +$ sudo dnf install sl -y +``` + +Now, just type **sl** to try it out. + + + +You may notice, as I did, that **Ctrl+C** doesn't derail your train, so you have to wait for the entire train to pass. That'll teach you to mistype **ls**! + +Want to check out the source to **sl**? It's over [on GitHub][2]. + +**sl** is also a great opportunity to share a personal PSA about open source licensing. While its [license][3] was "open source enough" to be packaged for my distribution, it's not technically an [OSI-approved][4] license. After the copyright line, the license reads simply: + +``` +Everyone is permitted to do anything on this program including copying, +modifying, and improving, unless you try to pretend that you wrote it. +i.e., the above copyright notice has to appear in all copies. +THE AUTHOR DISCLAIMS ANY RESPONSIBILITY WITH REGARD TO THIS SOFTWARE. +``` + +Unfortunately, when you chose a license that's not OSI-approved, you may accidentally be creating extra work for your users, as they must figure out whether your license will work for their situation. Do their corporate policies allow them to contribute? Can they even legally use the program? Does the license mesh with the license of another program they wish to integrate with it? + +Unless you're a lawyer (and perhaps, even if you are), navigating the space of non-standard licenses can be tricky. So if you're still looking for a New Year's Resolution, why not resolve to choose only OSI-approved licenses for any new projects you start in 2019. + +No disrespect to the creator, though. **sl** is still a great little command-line toy. + +Do you have a favorite command-line toy that you think I ought to profile? The calendar for this series is mostly filled out but I've got a few spots left. Let me know in the comments below, and I'll check it out. If there's space, I'll try to include it. If not, but I get some good submissions, I'll do a round-up of honorable mentions at the end. + +Check out yesterday's toy, [Box yourself in on the Linux command line][5], and check back tomorrow for another! + +-------------------------------------------------------------------------------- + +via: https://opensource.com/article/18/12/linux-toy-sl + +作者：[Jason Baker][a] +选题：[lujun9972][b] +译者：[译者ID](https://github.com/译者ID) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]: https://opensource.com/users/jason-baker +[b]: https://github.com/lujun9972 +[1]: https://opensource.com/users/bcotton +[2]: https://github.com/mtoyoda/sl +[3]: https://github.com/mtoyoda/sl/blob/master/LICENSE +[4]: https://opensource.org/licenses +[5]: https://opensource.com/article/18/12/linux-toy-boxes diff --git a/translated/talk/20180104 How Creative Commons benefits artists and big business.md b/translated/talk/20180104 How Creative Commons benefits artists and big business.md new file mode 100644 index 0000000000..5cfda766f5 --- /dev/null +++ b/translated/talk/20180104 How Creative Commons benefits artists and big business.md @@ -0,0 +1,59 @@ +知识共享是怎样造福艺术家和大企业的 +====== + + +我毕业于电影学院，毕业后在一所电影学校教书，之后进入一家主流电影工作室，我一直在从事电影相关的工作。创造业的方方面面面临着同一个问题：创造者需要原材料。有趣的是，自由文化运动提出了解决方案，具体来说是在自由文化运动中出现的知识共享组织。 + +###知识共享能够为我们提供展示片段和小样 + +和其他事情一样，创造力也需要反复练习。幸运的是，在我刚开始接触电脑时，就在一本渲染工场的专业杂志中接触到了开源这个存在。当时我并不理解所谓的“开源”是什么，但我知道只有开源工具能帮助我在领域内稳定发展。对我来说，知识共享也是如此。知识共享可以为艺术家们提供充满丰富艺术资源的工作室。 + +我在电影学院任教时，经常需要给学生们准备练习编辑、录音、拟音、分级、评分的脚本。在 Jim Munroe 的独立作品 [Infest Wisely][1] 中和 [Vimeo][2] 上的知识共享里我总能找到我想要的。这些写实的脚本覆盖内容十分广泛，从独立影院出品到昂贵的高质的升降镜头（一般都会用无人机代替）都有。 + +对实验艺术来说，确有无尽可能。知识共享提供了丰富的底片材料，这些材料可以用来整合，混剪等等，可以满足一位视觉先锋能够想到的任何用途。 + +在接触知识共享之前，如果我想要使用写实脚本，我只能用之前的学生和老师拍摄的或者直接使用版权库里的脚本，但这些都有很多局限性。 + +###坚守版权的底线很重要 + +知识共享同样能够创造经济效益。在某大型计算机公司的渲染工场工作时，我负责在某些硬件设施上测试渲染的运行情况，而这个测试时刻面临着被搁置的风险。做这些测试时，我用的都是[大雄兔][3]的资源，因为这个电影和它的组件都是可以免费使用和分享的。如果没有这个小短片，在接触写实资源之前我都没法完成我的实验，因为对于一个计算机公司来说，雇佣一只3D艺术家来应召布景是不太现实的。 + +令我震惊的是，与开源类似，知识共享已经用我们难以想象的方式支撑起了大公司。知识共享的使用或有或无地影响着公司的日常程序，但它填补了不足，让工作流程顺利进行。我没见到谁在他们的书中将流畅工作归功于知识共享的应用，但它确实无处不在。 + +我也见过一些开放版权的电影，比如[辛特尔][4]，在最近的电视节目中播放了它的短片，那时的电视比现在的网络媒体要火得多。 + +###知识共享可以提供大量原材料 + +艺术家需要原材料。画家需要颜料，画笔和画布。雕塑家需要陶土和工具。数字内容编辑师需要数字内容，无论它是剪贴画还是音效或者是电子游戏里的成品精灵。 + +数字媒介赋予了人们超能力，让一个人就能完成需要一组人员才能完成的工作。事实上，我们大部分都好高骛远。我们想做高大上的项目，想让我们的成果不论是视觉上还是听觉上都无与伦比。我们想塑造的是宏大的世界，紧张的情节，能引起共鸣的作品，但我们所拥有的时间精力和技能与之都不匹配，达不到想要的效果。 + +是知识共享再一次拯救了我们，用 [Freesound.org][5], [Openclipart.org][6], [OpenGameArt.org][7] 等等网站上那些细小的开放版权艺术材料。通过知识共享，艺术家可以使用各种他们自己没办法创造的原材料，来完成他们原本完不成的工作。 + +最神奇的是，不用自己投资，你放在网上给大家使用的原材料就能变成精美的作品，而这是你从没想过的。我在知识共享上面分享了很多音乐素材，它们现在用于无数的专辑和电子游戏里。有些人用了我的材料会通知我，有些是我自己发现的，所以这些材料的应用可能比我知道的还有多得多。有时我会偶然看到我亲手画的标志出现在我从没听说过的软件里。我见到过我为[开源网站][8]写的文章在别处发表，有的是论文的参考文献，白皮书或者参考资料中。 + +###知识共享所代表的自由文化也是一种文化 + +“自由文化”这个说法过于累赘，文化，从概念上来说，是一个有机的整体。在这种文化中社会逐渐成长发展，从一个人到另一个。它是人与人之间的互动和思想交流。自由文化是自由缺失的现代世界里的特殊产物。 + +如果你也想对这样的局限进行反抗，想把你的思想、作品，你自己的文化分享给全世界的人，那么就来和我们一起，使用知识共享吧！ + +-------------------------------------------------------------------------------- + +via: https://opensource.com/article/18/1/creative-commons-real-world + +作者：[Seth Kenlon][a] +译者：[译者ID](https://github.com/译者ID) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]:https://opensource.com/users/seth +[1]:http://infestwisely.com +[2]:https://vimeo.com/creativecommons +[3]:https://peach.blender.org/ +[4]:https://durian.blender.org/ +[5]:http://freesound.org +[6]:http://openclipart.org +[7]:http://opengameart.org +[8]:https://opensource.com/ diff --git a/translated/talk/20180208 Gathering project requirements using the Open Decision Framework.md b/translated/talk/20180208 Gathering project requirements using the Open Decision Framework.md new file mode 100644 index 0000000000..ea4dced8f8 --- /dev/null +++ b/translated/talk/20180208 Gathering project requirements using the Open Decision Framework.md @@ -0,0 +1,40 @@ +使用开放决策框架收集项目需求 +====== + + + +众所周知，明确、简洁和可衡量的需求会带来更多成功的项目。一项关于[麦肯锡与牛津大学][1]的大型项目的研究表明：“平均而言，大型 IT 项目超出预算 45％，时间每推移 7％，价值就比预期低 56％ “。该研究还表明，造成这种失败的一些原因是“模糊的业务目标，不同步的利益相关者以及过度的返工”。 + +业务分析师经常发现自己通过持续对话来构建这些需求。为此，他们必须吸引多个利益相关方，并确保参与者提供明确的业务目标。这样可以减少返工，提高更多项目的成功率。 + +他们可以用开放和包容的方式做到这一点。 + +### 成功的框架 + +提高项目成功率的一个工具是[开放决策框架][2]。开放决策框架是一种资源，可以帮助用户在拥抱[开放原则][3]的组织中做出更有效的决策。该框架强调三个主要原则：透明、包容、以客户为中心。 + +**透明**。很多时候，开发人员和产品设计人员都认为他们知道利益相关者如何使用特定工具或软件。但这些假设往往是不正确的，并导致对利益相关者实际需求的误解。开发人员和企业主讨论时实行透明势在必行。开发团队不仅需要了解一些好的情景，还需要了解利益相关方面对某些工具或流程所面临的挑战。提出诸如以下问题：“必须手动完成哪些步骤？”以及“这个工具是否按预期运行？”这提供了对问题的共同理解和讨论的基准。 + +**包容**。对于业务分析师来说，在收集需求时观察肢体语言和视觉暗示非常重要。如果有人双臂交叉或睁着眼睛坐着，那么这清楚地表明他们感觉没被聆听。业务分析师必须鼓励那些不被聆听的人公开交流，并给他们机会被聆听。在开始会议之前，制定基本规则，使所有人都能发表意见并分享他们的想法。聆听提供的反馈，并在收到反馈时礼貌地回复。多样化的意见和协作解决问题将为会议带来令人兴奋的想法。 + +**以顾客为中心**。以客户为中心的第一步是识别客户。谁从这种变化、更新或开发中受益？在项目早期，进行利益相关者映射，以帮助确定关键利益相关者，他们在项目中的角色以及他们适应大局的方式。让合适的客户参与并确保满足他们的需求将会确定更成功的要求，进行更现实（现实）的测试，并最终成功交付。 + +当你的需求会议透明、包容和以客户为中心时，你将收集更好的需求。当你使用[开放决策框架][4]来进行会议时，参与者会感觉有更多参与与授权，他们会提供更准确和完整的需求。换一种说法： + +**透明+包容+以客户为中心=更好的需求=成功的项目** + +-------------------------------------------------------------------------------- + +via: https://opensource.com/open-organization/18/2/constructing-project-requirements + +作者：[Tracy Buckner][a] +译者：[geekpi](https://github.com/geekpi) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]:https://opensource.com/users/tracyb +[1]:http://calleam.com/WTPF/?page_id=1445 +[2]:https://opensource.com/open-organization/resources/open-decision-framework +[3]:https://opensource.com/open-organization/resources/open-org-definition +[4]:https://opensource.com/open-organization/16/6/introducing-open-decision-framework \ No newline at end of file diff --git a/translated/talk/20180409 5 steps to building a cloud that meets your users- needs.md b/translated/talk/20180409 5 steps to building a cloud that meets your users- needs.md deleted file mode 100644 index 09ac1aced2..0000000000 --- a/translated/talk/20180409 5 steps to building a cloud that meets your users- needs.md +++ /dev/null @@ -1,108 +0,0 @@ - -构建满足客户需求的一套云环境的5个步骤 -====== - - -这篇文是和[Ian Teksbury][1]共同完成的。 - -无论你如何定义，云就是你的用户展现组织价值的另一个工具。当谈论新的范例或者技术的时候是很容易被，(云是两者兼有)它的新特性所分心。由一系列无止境的问题引发的对话能够很快的被发展为功能愿景清单，所有的这些都是你可能已经考虑到的。 - * 是公有云，私有云还是混合云？ - * 将会使用虚拟机还是容器，或者是两者？ - * 将会提供自助服务吗？ - * 将会完全自动的从开发转移到生产，还是它将需要手动操作？ - * 我们能以多块的速度创建？ - * 关于工具X,Y,还有Z？ - -这样的清单还可以列举很多。 - -开始现代化，或者数字转型，无论你是如何称呼的，通常方法是开始回答高级管理层的一些高层次问题，这种方法的结果是可以预想到的：失败。经过大范围的调研并且花费了数月的时间，如果不是几年，部署这个最炫的新技术，新的云技术从未被使用过而且陷入了荒废直到它最终被丢弃或者遗忘在数据中心的一角和预算中。 - -因为无论你交付的是什么工具都不是用户所想要或者需要的。更加糟糕的是，当用户真正需要的是一个单独的工具时，一系列其他的工具就会被用户抛弃因为新的,闪光的 -升级的工具能够更好的满足他们的需求。 - -### 议题聚焦 - -问题是关注，传统一直是关注工具。但工具并不是要增加到组织价值中的东西；终端用户利用它做什么。你需要将你的注意力从创建云(列入技术和工具)转移到你的人员和用户身上。 - -事实上，使用工具的用户(而不是工具本身)是驱动价值的因素，聚焦注意力在用户身上也是由其他原因的。工具是给用户使用去解决他们的问题并允许他们创造价值的， -所有这就导致了如果那些工具不能满足那些用户的需求，那么那些工具将不会被使用。如果你交付给你的用户的工具并不是他们喜欢的，他们将不会使用，这就是人类的 -人性行为。 - -数十年来，IT产业只为用户提供一种解决方案，因为仅有一个或两个选项，用户是没有权力去改变的。现在情况已经不同了。我们现在生活在一个技术选择的世界中。 -不给用户一个选择的机会的情况将不会被接受的；他们在个人的科技生活中有选择，同时希望在工作中也有选择。现在的用户都是受过教育的并且知道将会有比你提供的机会更好的选择。 - -因此，在物理上的最安全的地点之外，没有能够阻止他们只做他们自己想要的东西的方法，我们称之为“影子IT。”如果你的组织由如此严格的安全策略和承诺策略，许多员工将会感到灰心丧气并且会离职去其他能提供更好机会的公司。 - -基于以上所有的原因，你必须牢记要首先和你的终端用户设计你的昂贵又费时的云项目。 - -### 创建满足用户需求的云五个步骤的过程 - -既然我们已经知道了为什么，接下来我们来讨论一下怎么做。你如何去为终端用户创建一个云？你怎样重新将你的注意力从技术转移到使用技术的用户身上？ -根据以往的经验，我们知道最好的方法中包含两件重要的事情：从你的用户中得到及时的反馈，创建中和用户进行更多的互动。 - -你的云环境将继续随着你的组织不段发展。下面的五个步骤将会帮助你创建满足用户需求的云环境。 - -### 1\. 识别谁将是你的用户 - -在你开始询问用户问题之前，你首先必须识别谁将是你的新的云环境的用户。他们可能包括将在云上创建开发应用的开发者。也可能是运营，维护或者或者创建云的运维团队；还可能是保护组织的安全团队。在第一次迭代时，将你的用户数量缩小至人数较少的小组防止你被大量的反馈所淹没，让你识别的每个小组指派两个代表(一个主要的一个辅助的)。这将使你的第一次交付在大小和时间上都很小。 - -#### 2\. 和你的用户面对面的交谈来收获有价值的输入。 - -The best way to get users' feedback is through direct communication. Mass emails asking for input will self-select respondents—if you even get a response. Group discussions can be helpful, but people tend to be more candid when they have a private, attentive audience. -获得反馈的最佳途径是和用户直接交谈。如果你收到回复，大量的邮件要求你输入信息，你会选择自动回复。小组讨论会很有帮助的，但是当人们有私密的，吸引人注意的观众，他们会比较的坦诚。 - -和你的第一批用户安排面对面的个人的会谈并且向他们询问以下的问题： - - * 为了完成你的任务，你需要什么？ - * 为了完成你的任务，你想要什么？ - * 你现在最头疼的技术点是什么？ - * 你现在最头疼的政策或者程序是哪个？ - * 为了满足你的需求你有什么想法，欲望还是疼痛？ - -这些问题只是指导性的并不一定适合每个组。你不应该只询问这些问题，他们应该导向更深层次的讨论。确保告诉用户任何所说的和被问的都会被反馈的。所有的反馈都是有帮助的，无论是消极的还是积极的。这些对话将会帮助你设置你的开发优先级。 - -收集这种个性化的反馈是保持初始用户群较小的另一个原因：将会花费你大量的时间来和每个用户交流，但是我们已经发现这是相当值得付出的投入。 - -#### 3\. 设计并交付你的解决方案的第一个版本 - -一旦你收到初始用户的反馈，就是时候开始去设计并交付一部分的功能了。我们不推荐尝试一次性交付整个解决方案。设计和交付的时期要短；这是为了避免犯一个需要你花费一年的时间去寻找解决方案的错误，只会让你的用户拒绝它，因为对他们来说毫无用处。创建你的云所需要的工具取决于你的组织和它的特殊需求。只需确保你的解决方案是建立在用户的反馈的基础上的，你将功能小块化的交付并且要经常的去征求用户的反馈。 - -#### 4\. 询问用户对第一个版本的反馈 - -太棒了，现在你已经设计并向你的用户交付了你的炫酷的新的云环境的第一个版本！你并不是花费一整年去完成它而是将它处理成小的模块。为什么将其分为小的模块如此重要呢？因为你要回归你的用户并且向他们收集关于你的设计和交付的功能。他们喜欢什么？不喜欢什么?你正确的处理了他们所关注的吗？是技术功能上很厉害，但系统进程或者策略方面仍然欠缺？ - -再重申一次，你要问的问题取决于你的组织；这里的关键是继续前一个阶段的讨论。毕竟你正在为用户创建云环境，所以确保它对用户来说是有用的并且能够有效利用每个人的时间。 - -#### 5\. 回到第一步。 - -这是一个互动的过程。你的第一次交付应该是快速而小规模的，而且以后的迭代也应该是这样的。不要期待仅仅按照这个流程完成了一次，两次即使是三次就能完成。 -一旦你持续的迭代，你将会吸引更多的用户从而能够在这个过程中得到更好的回报。你将会从用户那里得到更多的支持。你能狗迭代的更迅速并且更可靠。到最后，你 -将会通过改变你的进程来满足用户的需求。 - -用户是这个过程中最重要的一部分，但迭代是第二重要的因为它让你能够回到用户中进行持续沟通从而得到更多有用的信息。在每个阶段，记录那些是有效的哪些没有起到应有的效果。要自省，要对自己诚实。我们所花费的时间提供了最有价值的了吗？如果不是，在下一个阶段尝试些不同的。在每次循环中不要花费太多时间的重要部分是，如果某部分在这次不起作用，你能够很容易的在写一次中调整它，知道你找到能够在你组织中起作用的方法。 - -### 这仅仅是开始 - -通过许多客户的约定，从他们那里收集反馈，以及在这个领域的同行的经验，我们一次次的发现在你创建云的时候最重要事就是和你的用户交谈。这看起来是很明显的， -但很让人惊讶的是很多组织却偏离了这个方向去花费数月或者数年的时间去创建，然后最终发现它对终端用户甚至一点用处都没有。 - -现在你已经知道为什么你需要将你的注意力集中到终端用户身上并且在中心节点和用户有一个一起创建云的互动过程。剩下的是我们所喜欢的部分，你出去做的部分。 - -这篇文章是基于"[为终端用户设计混合云或者失败]，"一篇作者将在[Red Hat Summit 2018][3]上发表的文章，并且将于5月8日至10日在旧金山举行 - -[在5月7号前注册][3]将会节省US$500。在支付页面使用折扣码**OPEN18**将会享受到折扣。 --------------------------------------------------------------------------------- - -via: https://opensource.com/article/18/4/5-steps-building-your-cloud-correctly - -作者：[Cameron Wyatt][a] -译者：[FelixYFZ](https://github.com/FelixYFZ) -校对：[校对者ID](https://github.com/校对者ID) -选题：[lujun9972](https://github.com/lujun9972) - -本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 - -[a]:https://opensource.com/users/cameronmwyatt -[1]:https://opensource.com/users/itewk -[2]:https://agenda.summit.redhat.com/SessionDetail.aspx?id=154225 -[3]:https://www.redhat.com/en/summit/2018 diff --git a/translated/talk/20180412 A new approach to security instrumentation.md b/translated/talk/20180412 A new approach to security instrumentation.md new file mode 100644 index 0000000000..c177e8f5fe --- /dev/null +++ b/translated/talk/20180412 A new approach to security instrumentation.md @@ -0,0 +1,80 @@ +一种新的用于安全检测的方法 +====== + + + +我们当中有多少人曾说出过下面这句话：“我希望这能起到作用！”？ + +毫无疑问，我们中的大多数人可能都不止一次地说过这句话。这句话不是用来激发信心的，相反它揭示了我们对自身能力和当前正在测试功能的怀疑。不幸的是，这句话非常好地描述了我们传统的安全模型。我们的运营基于这样的假设，并希望我们实施的控制措施——从 web 应用的漏扫到终端上的杀毒软件——防止恶意的病毒和软件进入我们的系统，损坏或偷取我们的信息。 + +渗透测试通过积极地尝试侵入网络、向 web 应用注入恶意代码或者通过发送钓鱼邮件来传播病毒等等这些步骤来避免我们对假设的依赖。由于我们在不同的安全层面上来发现和渗透漏洞，手动测试无法解决漏洞被主动打开的情况。在安全实验中，我们故意在受控的情形下创造混乱，模拟事故的情形，来客观地检测我们检测、阻止这类问题的能力。 + +> “安全实验为分布式系统的安全性实验提供了一种方法，以建立对抗恶意攻击的能力的信心。” + +在分布式系统的安全性和复杂性方面，需要反复地重申混沌工程界的一句名言，“希望不是一种有效的策略”。我们多久会主动测试一次我们设计或构建的系统，来确定我们是否已失去对它的控制？大多数组织都不会发现他们的安全控制措施失效了，直到安全事件的发生。我们相信“安全事件不是侦察措施”，而且“希望不要出事也不是一个有效的策略”应该是 IT 专业人士执行有效安全实践的口号。 + +工业在传统上强调预防性的安全措施和纵深防御，但我们的任务是通过侦探实验来驱动对安全工具链新的知识和见解。因为过于专注于预防机制，我们很少尝试一次以上地或者年度性地手动测试要求的安全措施，来验证这些控件是否按设计的那样执行。 + +随着现代分布式系统中的无状态变量的不断改变，人们很难充分理解他们的系统的行为，因为会随时变化。解决这个问题的一种途径是通过强大的系统性的设备进行检测，对于安全性检测，你可以将这个问题分成两个主要方面，测试，和我们称之为实验的部分。测试是对我们已知部分的验证和评估，简单来说，就是我们在开始找之前，要先弄清楚我们在找什么。另一方面，实验是去寻找获得我们之前并不清楚的见解和知识。虽然测试对于一个成熟的安全团队来说是一项重要实践，但以下示例会有助于进一步地阐述两者之间的差异，并对实验的附加价值提供一个更为贴切的描述。 + +### 示例场景：精酿啤酒 + +思考一个用于接收精酿啤酒订单的 web 服务或者 web 应用。 + +这是这家精酿啤酒运输公司的一项重要服务，这些订单来自客户的移动设备，网页，和通过为这家公司精酿啤酒提供服务的餐厅的 API。这项重要服务运行在 AWS EC2 环境上，并且公司认为它是安全的。这家公司去年成功地通过了 PCI 规则，并且每年都会请第三方进行渗透测试，所以公司认为这个系统是安全的。 + +这家公司有时一天两次部署来进行 DevOps 和持续交付工作，公司为其感到自豪。 + +在了解了混沌工程和安全实验方面的东西后，该公司的开发团队希望能确定，在一个连续不断的基础上，他们的安全系统对真实世界事件的有效性和快速恢复性怎么样。与此同时，确保他们不会把安全控件不能检测到的新问题引入到系统中。 + +该团队希望能小规模地通过评估端口安全和防火墙设置来让他们能够检测、阻止和警告他们 EC2 安全组上端口设置的错误配置更改。 + + * 该团队首先对他们正常状态下的假设进行总结。 + * 在 EC2 实例里为端口安全进行一个假设。 + * 为未认证的端口改变实验选择和配置 YAML 文件。 + * 该配置会从已选择的目标中随机指定对象，同时端口的范围和数量也会被改变。 + * 团队还会设置进行实验的时间并缩小爆破攻击的范围，来确保对业务的影响最小。 + * 对于第一次测试，团队选择在他们的测试环境中运行实验并运行一个单独的测试。 + * 在真实的游戏日风格里，团队在预先计划好的两个小时的窗口期内，选择灾难大师来运行实验。在那段窗口期内，灾难大师会在 EC2 实例安全组中的一个上执行这次实验。 + * 一旦游戏日结束，团队就会开始进行一个彻底的、无可指责的事后练习。它的重点在于针对稳定状态和原始假设的实验结果。问题会类似于下面这些： + + + +### 事后验证问题 + + * 防火墙是否检测到未经授权的端口更改？ + * 如果更改被检测到，更改是否会被阻止？ + * 防火墙是否会将有用的日志信息记录到日志聚合工具中？ + * SIEM 是否会对未经授权的更改发出警告？ + * 如果防火墙没有检测到未经授权的更改，那么配置的管理工具是否发现了这次更改？ + * 配置管理工具是否向日志聚合工具报告了完善的信息？ + * SIEM 最后是否进行了关联报警？ + * 如果 SIEM 发出了警报，安全运营中心是否能收到这个警报？ + * 获得警报的 SOC 分析师是否能对警报采取措施，还是缺少必要的信息？ + * 如果 SOC 确定警报是真实的，那么安全事件响应是否能简单地从数据中进行分类活动？ + + + +我们系统中对失败的承认和预期已经开始揭示我们对系统工作的假设。我们的使命是利用我们所学到的，并更加广泛地应用它。以此来真正主动地解决安全问题，来超越当前传统主流的被动处理问题的安全模型。 + +随着我们继续在这个新领域内进行探索，我们一定会发布我们的研究成果。如果您有兴趣想了解更多有关研究的信息或是想参与进来，请随时联系 Aaron Rinehart 或者 Grayson Brewer。 + +特别感谢 Samuel Roden 对本文提供的见解和想法。 + +**[看我们相关的文章，是否需要 DevSecOps 这个词？][3]]** + +-------------------------------------------------------------------------------- + +via: https://opensource.com/article/18/4/new-approach-security-instrumentation + +作者：[Aaron Rinehart][a] +译者：[hopefully2333](https://github.com/hopefully2333) +校对：[校对者ID](https://github.com/校对者ID) +选题：[lujun9972](https://github.com/lujun9972) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]:https://opensource.com/users/aaronrinehart +[1]:https://twitter.com/aaronrinehart +[2]:https://twitter.com/BrewerSecurity +[3]:https://opensource.com/article/18/4/devsecops diff --git a/translated/talk/20180904 Why schools of the future are open.md b/translated/talk/20180904 Why schools of the future are open.md new file mode 100644 index 0000000000..63fb900ebf --- /dev/null +++ b/translated/talk/20180904 Why schools of the future are open.md @@ -0,0 +1,50 @@ +Why schools of the future are open +====== + + + +最近有些人和我说现代教育会是什么样子,我回答说:就像过去一百年一样。我们为什么会对我们的教育系统保持悲观态度呢? + +这不是一个悲观的观点,而是一个务实的观点。鉴于任何把时间花在学校的人都想离开舒适区，所以我们教导年轻人怎么去固执的抵制变革。美国学校新的学年开始，大多数学生返回学校把桌子排成一排。教学环境主要以教师为中心，进步由卡内基单位和A-F评分来衡量，合作通常被认为是作弊。 + +我们从哪能够找到证据指出这种工业化模式正在产生所预想的结果，每个孩子都得到个人关注，以培养对学习的热爱，并发展出当今创新经济中茁壮成长所需的技能，然后我们可以非常满足了。 但是，任何真实客观地看待当前的指标都表明要从基本开始改变。 + + +但我的观点并非悲观。 事实上，非常乐观。 + +尽管我们可以很容易的阐述现代教育的问题所在，但我也知道一个例子，教育利益相关者愿意走出哪些舒适的环境，并挑战这个对变革免疫的系统。 教师要求与同龄人进行更多的合作，并采取更多方式公开透明的对原型创意进行展示，从而为学生带来真正的创新 - 而不是通过技术重新包装传统方法。 管理员通过以社区为中心，基于项目的学习，实现更深入，更紧密的学习实际的应用程序 - 不仅仅是在孤立的教室中“做项目”。 父母们想把学习的快乐回归到学校的文化，这些文化因强调考试而受到损害。 + +所有文化变革向来都不容易，特别是在面对任何考试成绩下降导致政治反对的环境中,人们不愿意承担风险（无论统计意义如何重要）。 +那么为什么我乐观地认为我们正在接近一个临界点，我们所需要的变化确实可以克服长期挫败它们的惯性？ + +因为在我们的现代时代，社会中还有其他东西在以前没有出现过：开放的精神，由数字技术催化。 + +想一想：如果你需要为即将到来的法国旅行学习基本的法语，你该怎么办？ 您可以在当地社区学院注册一门课程或者从图书馆借书，但很有可能，您会用免费在线视频并了解旅行所需的基本知识。 人类历史上从未有过免费的按需学习。 事实上，现在正在参加麻省理工学院关于“[应用数学的专题：线性代数和变异微积分][1]的免费在线课程。报名参加！ + +为什么麻省理工学院，斯坦福大学和哈佛大学等学校提供免费课程？ 为什么人们和公司愿意公开分享曾经严格控制的知识产权？ 为什么全球各地的人们都愿意花时间 - 无偿 - 帮助公民科学项目？ + +在我们的现代，还有其他东西在以前没有出现过：在数字技术的催化下，开放的精神。 + +作者David Price在他那本很棒的书[开放：我们将如何在未来工作和学习][2]中，清楚地描述了非正式的社交学习如何成为新的学习规范，尤其是习惯于能够及时获取他们需要的知识学习的年轻人。通过一系列案例研究，Price清楚地描绘了当传统制度不适应这种新现实并因此变得越来越不相关时会发生什么。 这是缺失的元素，它能让众包产生积极的颠覆性的影响。 + +Price指出（以及人们现在对基层的要求）正是一场开放的运动，人们认识到开放式合作和自由交换思想已经破坏了从音乐到软件再到出版的生态系统。 而且，除了任何自上而下推动的“改革”之外，这种对开放性的期望有可能从根本上改变长期以来一直抵制变革的教育体系。 事实上，开放精神的标志之一是，它期望知识的透明和公平民主化，造福所有人。 那么，对于这样一种精神而言，还有什么生态系统比试图让年轻人做好准备，继承这个世界、让这个世界变得更好呢？ + +当然，也有另一种悲观的声音说，我早期关于教育未来的预测可能确实是短期未来的教育状况。 但我也非常乐观地认为，这种说法将被证明是错误的。 我知道我和许多其他志趣相投的教育工作者每天都在努力证明这是错误的。 当我们开始帮助我们的学校[转变为组织机构][3] - 从过时的传统模式过渡到更开放，灵活，响应每个学生和他们服务的社区需要的时候，你会加入我吗 + +这是适合现代时代的真正教育模式 + +-------------------------------------------------------------------------------- + +via: https://opensource.com/open-organization/18/9/modern-education-open-education + +作者：[Ben Owens][a] +选题：[lujun9972](https://github.com/lujun9972) +译者：[译者ID](https://github.com/hkurj) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]: https://opensource.com/users/engineerteacher +[1]: https://ocw.mit.edu/courses/mechanical-engineering/2-035-special-topics-in-mathematics-with-applications-linear-algebra-and-the-calculus-of-variations-spring-2007/ +[2]: https://www.goodreads.com/book/show/18730272-open +[3]: https://opensource.com/open-organization/resources/open-org-definition diff --git a/translated/talk/20181112 A Free Guide for Setting Your Open Source Strategy.md b/translated/talk/20181112 A Free Guide for Setting Your Open Source Strategy.md new file mode 100644 index 0000000000..16216c8a46 --- /dev/null +++ b/translated/talk/20181112 A Free Guide for Setting Your Open Source Strategy.md @@ -0,0 +1,66 @@ +[#]: collector: (lujun9972) +[#]: translator: (geekpi) +[#]: reviewer: ( ) +[#]: publisher: ( ) +[#]: subject: (A Free Guide for Setting Your Open Source Strategy) +[#]: via: (https://www.linux.com/blog/2018/11/free-guide-setting-your-open-source-strategy) +[#]: author: ([Amber Ankerholz](https://www.linux.com/users/aankerholz) +[#]: url: ( ) + +制定开源战略的免费指南 +====== + + + +大多数使用开源的公司都了解其商业价值，但他们可能缺乏战略性地实施开源计划和获得全部回报的工具。根据 [The New Stack][1] 最近的一项调查，“开源计划的三大好处是1）提高了对开源的认识，2）提高了开发周期的速度和灵活性，以及 3）更好的许可证合规性“。 + +运营开源计划办公点涉及创建策略来帮助你定义和实施你的方法，并衡量你的进度。由 Linux 基金会与 TODO 集团合作开发的[企业开源指南][2]基于多年的经验和实践提供了专业开源知识。 + +最新的指南中，[设置开源战略][3]详细介绍了制定战略和确保成功之路的基本步骤。根据该指南，“你的开源战略将管理、参与和创建开源软件的计划与计划所服务的业务目标联系起来。这可以开辟许多机会并促进创新。“该指南涵盖以下主题： + + 1. 为什么制定战略？ + 2. 你的战略文件 + 3. 战略方法 + 4. 关键考虑因素 + 5. 其他组成 + 6. 确定投资回报率 + 7. 投资目标 + + + +这里关键的第一步是创建和记录你的开源策略，该策略将“帮助你最大限度地提高组织从开源中获得的利益。”同时，你详细的策略可以帮助你避免因错误而导致的困难，例如：选择错误的许可证或不正确地维护代码。根据指南，该文件还可以： + + * 让领导者感到兴奋并参与 + * 帮助在公司内获得支持 + * 促进分散的多部门组织的决策 + * 帮助建立一个健康的社区 + * 解释贵公司的开源方式和对其使用的支持 + * 明确贵公司在社区驱动的外部研发中投资的地方，以及贵公司将重点放在增值差异化的地方 + + + +Salesforce 的软件架构师兼指南的撰稿人 Ian Varley 说：“在 Salesforce 内，我们有内部文件，我们将这些围绕开源战略指导和鼓励的文件分发给我们的工程团队。其中鼓励创建和使用开源，这让他们毫不含糊地知道公司的战略领导者完全支持它。此外，如果有某些我们不希望工程师使用的许可证或有其他开源指南，我们的内部文档需要明确。“ + +开源计划有助于促进企业文化，使企业更高效，并且根据指南，强有力的战略文档可以“帮助你的团队了解开源计划背后的业务目标，确保更好的决策，并最大限度地降低风险“。 + +了解如何使用[设置开源策略][3]新指南中的提示和经过验证的实践，将管理和创建开源软件的目标与组织的业务目标保持一致。然后，查看所有 12 个[企业开源指南][2]，了解有关使用开源获得成功的更多信息。 + +本文最初发表在 [Linux基金会][4] + +-------------------------------------------------------------------------------- + +via: https://www.linux.com/blog/2018/11/free-guide-setting-your-open-source-strategy + +作者：[Amber Ankerholz][a] +选题：[lujun9972][b] +译者：[geekpi](https://github.com/geekpi) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]: https://www.linux.com/users/aankerholz +[b]: https://github.com/lujun9972 +[1]: https://thenewstack.io/open-source-culture-starts-with-programs-and-policies/ +[2]: https://www.linuxfoundation.org/resources/open-source-guides/ +[3]: https://www.linuxfoundation.org/resources/open-source-guides/setting-an-open-source-strategy/ +[4]: https://www.linuxfoundation.org/blog/2018/11/a-free-guide-for-setting-your-open-source-strategy/ \ No newline at end of file diff --git a/translated/tech/20171108 Continuous infrastructure- The other CI.md b/translated/tech/20171108 Continuous infrastructure- The other CI.md new file mode 100644 index 0000000000..1e8395e80f --- /dev/null +++ b/translated/tech/20171108 Continuous infrastructure- The other CI.md @@ -0,0 +1,111 @@ +持续基础设施： 另一个 CI +====== + + + +持续交付（CD）和持续集成（CI）是 DevOps 的两个众所周知的方面。但在 CI 大肆流行的今天却忽略了另一个关键性的 "I"：基础设施（infrastructure）。 + +曾经有一段时间 “基础设施”就意味着无头的黑盒子，庞大的服务器，和高耸的机架——更不用说漫长的采购流程和对盈余负载的错误估计。后来到了虚拟机时代，把基础设施处理得很好，虚拟化——以前的世界从未有过这样。我们不再需要管理实体的服务器。仅仅是简单的点击，我们就可以创建和销毁，开始和停止，升级和降级我们的服务器。 + +有一个关于银行的流行的故事，它们实现了数字化，并且引入了在线表格，用户需要手动填写表格，打印，然后邮寄回银行。这就是我们今天要说的基础设施：使用新技术来做和以前一样的事情。 + +在这篇文章中，我们会看到在基础设施管理方面的进步，将基础设施视为一个版本化的组件并试着探索服务器一致性的概念。在后面的文章中，我们将了解如何使用开源工具来实现持续的基础设施。 + +![continuous infrastructure pipeline][2] + +实践中的持续集成管道 + +这是我们熟悉的 CI，尽早发布，经常发布的循环管道。这个管道缺少一个关键的组件：基础设施。 + +突击小测试： + + * 你怎样创建和升级你的基础设施？ + * 你怎样控制和追溯基础设施的改变？ + * 你的基础设施是如何与你的业务进行匹配的？ + * 你是如何确保在正确的基础设施配置上进行测试的？ + +要回答这些问题，就要了解持续基础设施。把 CI 构建流程分为代码持续集成（CIc）和基础设施持续集成（CIi）来并行开发代码和基础设施，再将两者融合到一起进行测试 。把基础设施构建视为CI流程中的重要的一环。 + +![pipeline with infrastructure][4] + +包含持续基础设施的 CI 管道流程 + +关于 CIi 定义的几个方面： + +**1\. 代码** + +通过代码来创建基础设施架构，而不是通过安装。使用配置脚代码是现代最流行的创建基础设施（IaC）的方法。这些脚本遵循典型的编码和单元测试周期（请参阅下面关于 Terraform 脚本的示例）。 + +**2\. 版本** + +IaC 组件在源码仓库中进行版本管理。这让基础设施的拥有了版本控制的所有好处：一致性，可追溯性，分支和标记。 + +**3\. 管理** + +通过编码和版本化的基础设施管理，你可以使用你所熟悉的测试和发布流程来管理基础设施的开发。 + +CIi 提供了下面的这些优势： + +**1\. 一致性** + +版本化和标记基础设施意味着你可以清楚的知道你的系统使用了哪些组件和配置。这是建立了一个非常好的 DevOps 实践，用来鉴定和管理基础设施的一致性。 + +**2\. 可重现性** + +通过基础设施的标记和基线，重建基础设施变得非常容易。想想你是否经常听到这个：“但是它在我的机器上可以运行！”现在，你可以在本地的测试平台中快速重现类似生产环境，从而将环境像变量一样在你的调试过程中删除。 + +**3\. 可追溯性性** + +你是否还记得曾经有过多少次寻找到底是谁更改了文件夹权限的经历，或者是谁升级了 `ssh` 包？编码，版本化，发布的基础设施消除了临时的变更，为基础设施的管理带来了可追踪性和可预测性。 + +**4\. 自动化** + +借助脚本化的基础架构，自动化是下一个合乎逻辑的步骤。自动化允许你按需创建基础设施，并在使用完成后删除它，所以你可以将更多宝贵的时间和精力用在更重要的任务上。 + +**5\. 不变性** + +CIi 不可变基础设施等创新。你可以创建一个新的基础设施组件而不是通过升级（请参阅下面有关不可变设施的说明）。 + +持续基础设施是从运行基础环境到运行基础组件的进化。像处理代码一样，通过认证的 DevOps 流程来完成。对传统的 CI 的重新定义包含了缺少的那个 “i”，从而形成了连贯的 CD 。 + +**(CIc + CIi) = CI -> CD** + +## 基础设施代码 （IaC） + +CIi 管道的一个关键推动因素是基础设施代码（IaC）。IaC 是一种使用配置文件进行基础设施创建和升级的机制。这些配置文件像其他的代码一样进行开发，并且使用版本管理系统进行管理。这些文件遵循一般的代码开发流程：单元测试，提交，构建，和发布。IaC 流程拥有版本控制带给基础设施开发的所有好处，像标记，版本一致性，和修改可追溯。 + +这有一个简单的 Terraform 脚本用来用来在 AWS 上创建一个双层基础设施的简单示例，包括虚拟私有云（VPC）,弹性负载（ELB），安全组和一个 NGINX 服务器。Terraform 是一个通过通过脚本创建和更改基础设施架构和开源工具。 + +![terraform script][7] + +Terraform 脚本创建双层架构设施的简单示例 + +完整的脚本请参见 [GitHub][8]。 + +## 基础设施架构的不变性 + +你有几个正在运行的 VM 需要更新安全补丁。一个常见的做法是推送一个远程脚本单独更新每个系统。 + +如何更新一个旧系统，如何丢弃它们并布置安装了新安全补丁的新系统？这就是基础设施的不变性。通过之前对基础设施的版本控制和标记，所以安装补丁只需要更新下脚本并将其推送到发布管道即可。 + +现在你知道为什么要说基础设施在 CI 管道中特别重要了吗？ + +-------------------------------------------------------------------------------- + +via: https://opensource.com/article/17/11/continuous-infrastructure-other-ci + +作者：[About The Author;Girish Managoli;With About Years;Experience In The Software It Industry;Girish Presently Holds Chief Architect Capacity At Mindtree;A Global It Services Organization;Based In India. Specialising In Paas;Saas Platforms;Girish Is Architect Of;I Got][a] +译者：[lujun9972](https://github.com/lujun9972) +校对：[Jamskr](https://github.com/Jamskr) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]:https://opensource.com +[1]:/file/376916 +[2]:https://opensource.com/sites/default/files/images/life-uploads/figure1.jpg (continuous infrastructure pipeline in use) +[3]:/file/376921 +[4]:https://opensource.com/sites/default/files/images/life-uploads/figure2.jpg (CI pipeline with infrastructure) +[5]:https://github.com/hashicorp/terraform +[6]:/file/376926 +[7]:https://opensource.com/sites/default/files/images/life-uploads/figure3_0.png (sample terraform script) +[8]:https://github.com/terraform-providers/terraform-provider-aws/tree/master/examples/two-tier diff --git a/translated/tech/20171111 A CEOs Guide to Emacs.md b/translated/tech/20171111 A CEOs Guide to Emacs.md new file mode 100644 index 0000000000..5b25f37313 --- /dev/null +++ b/translated/tech/20171111 A CEOs Guide to Emacs.md @@ -0,0 +1,278 @@ +一位 CEO 的 Emacs 指南 +============================================================ + +几年前，不，是几十年前，我就在用 Emacs。不论是码代码、编写文档，还是管理邮件和日程，我都用这个编辑器或者是说操作系统，而且我还乐此不疲。多年过去了，我也转向了其他更新，更好的工具。结果，我已经忘了如何在不用鼠标的情况下来浏览文件。大约三个月前，我意识到我在应用程序和计算机之间切换上耗费了大量的时间，于是就决定再试一次 Emacs。这是个很正确的决定，原因有以下几个。其中包括了 `.emacs` 和 Dropbox 的技巧，可以让你建立一个良好的，可移植的环境。 + +对于那先还没用过 Emacs 的人来说，你可能会讨厌它，但也可能喜欢上它。它有点像一个房子大小的 Rube Goldberg 机器，乍一看，它具备烤面包机的所有功能。这听起来不像是一种认可，但关键短语是“乍一看”。一旦你了解了Emacs，你就会意识到它其实是一种可以作为发动机的热核烤面包机。好吧，你想对文字做什么都可以。当考虑到计算寿命在很大程度上与文本有关时，这是一个相当大胆的声明，真的很大胆。 + +也许对我来说更重要的是，它是我曾经使用过的一个应用程序，并让我觉得我真正的拥有它，而不是把我塑造成一个匿名的“用户”，就好像位于 [Soma][30] 或 Redmond 附近某个高档办公室的产品营销部门把钱作为明确的目标一样。现代生产力和创作应用程序（如文件或 `IDE`）就像碳纤维赛车，他们装备得很好，也很完整。而Emacs 就像一盒经典的 [Campagnolo][31] 零件和一个漂亮的拖钢框架，缺少曲柄臂和刹车杆，你必须在网上某个小众文化中找到它们。第二点就是它会给你带来无尽的快乐或烦恼，这取决于你自己，而且会一直持续到你生命的最后一天。我是那种在找到一堆老古董或用 `Emacs Lisp` 配置编辑器时同样感到高兴的人，具体情况因人而异。 + + +一辆我还在骑的1933年产的钢制自行车。你可以从查看框架管差别： [https://www.youtube.com/watch?v=khJQgRLKMU0][6]. + +这可能给人一种 Emacs 已经过气或过时的印象。但它不是，它是强大和永恒的，只要你耐心地去理解它的一些规则。他的规则很另类，也很奇怪，但其中的逻辑却引人注目，且很有魅力。对于我来说， Emacs 更像是未来而不是过去。就像牵引式钢框架在未来几十年里将会变得好用和舒适，而神奇的碳纤维自行车将会被扔进垃圾场，在撞击中粉碎一样，Emacs 也将会作为一种在最新的流行应用早已被遗忘的时候的好用的工具继续存在这。 + +如果通过编辑 `Lisp` 代码来构建自己的个人工作环境，并将这种非常适合自己的环境移植到任何计算机的想法吸引了你，那么你可能会爱上 Emacs。如果你喜欢很潮、很炫的，又不想投入太多时间和精力的情况下就能直接工作的话，那么它可能不适合你。我已经不再写代码了（除了 `Ludwig` 和 `Emacs Lisp`），但是 `Fugue` 的很多工程师都使用 Emacs 来提高码代码的效率。我公司有 30% 的工程师用 Emacs， 40% 用 `IDE` 和 30% 的用 vim。但这篇文章是关于 CEO 和其他[聪明的老板][32]（PHB[1][7]）的 Emacs 指南，所以我将解释或者说辩解我为什么喜欢它以及我如何使用它。同时我也希望我能介绍清楚从而让你能有个良好的体验，而不是花上几个小时去 Google。 + +### 最后的优点 + +使用 Emacs 带来的长期优势是让生活更轻松。与最后的收获相比，最开始的付出完全值得。想想这些: + +### 无需上下文切换 + +`Org` 模式本身就值得花时间，但如果你像我一样，你通常要处理十几份左右的文件 —— 从博客帖子到会议需要做什么的清单，再到员工评论。在现代计算世界中，这通常意味着要使用多个应用程序，所有这些应用程序都有不同的用户界面，保存方式、排序和搜索方式。结果就是你需要不断转换思维环境，记住细节。我讨厌上下文切换，因为它是一种强加到我身上的方式，原因是破坏了接口模型[2][8]，并且我讨厌记住计算机的命令，这本该是计算机要记住的东西。在单个环境下，Emacs 对 PHB 甚至比对于程序员更有用，因为程序员更多时候只需要专注于一个程序。转换思维环境的成本比通常看起来的要高。操作系统和应用程序供应商已经构建了各种接口，以分散我们对这一现实的注意力。如果你是技术人员，通过快捷键（`M-:`）来访问功能强大的[语言解释器][33]会方便的多[3][9]。 + +许多应用程序可以全天全屏并用于编辑文本。Emacs 是惟一的，因为它既是编辑器也是 `Emacs Lisp` 解释器。从本质上说，你工作时只要用电脑上的一两个键就能完成。如果你对编程略知一二，就能发现这一位置你可以在 Emacs 中做 _任何事情_。一旦你在内存中有了这些命令，你的电脑就可以在你工作时几乎实时地为你提供高效的运转。你不会想用 `Emacs Lisp` 来重建 Excel，只要用简单的一两行代码就能实现 Excel 中大多数的功能。如果我需要处理数字，我更有可能转到 scratch 缓冲区，编写一些代码，而不是打开电子表格。即便是我有一封多行的邮件要写，我通常也会先在 Emacs 中写完，然后再复制粘贴到邮件客户端中。当你可以流畅的书写时，为什么要去切换呢？你可以先从一两个简单的计算开始，随着时间的推移，你可以很容易的在 Emacs 中添加你所需要处理的计算。这在应用程序中可能是独一无二的，同时还提供了让为其他的人创造的丰富特性。还记得 Isaac Asimov 书中那些神奇的终端吗[4][10]？ Emacs 是我所遇到的最接近他们的东西。我决定不再用什么应用程序来做这个或那个。相反，我只是工作。拥有一个伟大的工具并致力于此，这才是真正的动力和效率。 + +### 在安静中创造事情 + +拥有我所发现的最好的文本编辑功能的最终结果是什么？有一群人在做各种各样有用的补充吗？拥有 `Lisp` 键盘的全部功能？这就是我用 Emacs 来完成所有的创作性工作，处理音乐和图片除外。 + +我的办公桌上有两个显示器。其中一块竖屏是将 Emacs 全天全屏显示，另一个显示浏览器，用来搜索和阅读，通常也会打开一个终端。我将日历、邮件等保存在 OS X 的另一个桌面上，当我使用 Emacs 时，这个桌面是隐藏的，同时我也会关掉所有通知。这样就能让我专注于我手头上在做的事了。我发现，在更现代的 UI 应用程序中，消除干扰几乎是不可能的，因为这些应用程序努力提供帮助并使其易于使用。我不需要经常被提醒该如何操作，我已经做了成千上万次了，我真正需要的是一张干净整洁的白纸用来思考。也许因为年龄和自己的“恶习”，我不太喜欢处在嘈杂的环境中，但我认为这值得一试。看看在你电脑环境中有一些真正的宁静是怎样的。当然，现在很多应用程序都有隐藏界面的模式，谢天谢地，苹果和微软现在都有了真正意义上的全屏模式。但是，没有并没有应用程序可以强大到足以“处理”大多数事务。除非你整天写代码，或者像写一本书一样处理很长的文档，否则你仍然会面临其他应用程序的干扰。而且，大多数现代应用程序似乎同时显得自视甚高，缺乏功能和可用性[5][11]。比其 office 应用程序，我更讨厌在线版的应用程序。 + + +我的桌面布局， Emacs 在左边 + +但是交流呢？创造和交流之间的差别很大。当我为两者留出不同的时间时，我的效率会更高。在 `Fugue` 中使用了 `Slack`，痛并快乐着。我把它和我的日历、电子邮件放在一个即时通讯的桌面上，这样，当我正在做事时，我很高兴地能够忽略所有的聊天。仅仅是风投或董事会董事的一次懈怠，或一封电子邮件，就能让我立刻丢掉手头工作。但是，大多数事情通常可以等上一两个小时。 + +### 带上一切，并保留着 + +第三个原因是，我发现 Emacs 比其它的环境更有优势的是你可以很容易的用它来处理事务。我的意思是，你所需要的只是通过 `Dropbox` 类似的网站同步一两个目录，而不是让大量的应用程序以它们自己的方式进行交互和同步。然后，你可以在任何地方，任何环境下工作了，因为你已经精心制作了适合目的套件了。我在 OS X，Windows，或有时在 Linux 都是这样做的。它非常简单可靠。这种功能很有用，以至于我害怕处理页面、Google Docs、Office 或其他类型的文件和应用程序，这些文件和应用程序会迫使我回到文件系统或云中的某个地方去寻找。 + +永久存储在计算机上的限制是文件格式。假设人类已经解决了存储[6][12]的问题，随着时间的推移，我们面临的问题是我们能否够继续访问我们创建的信息。文本文件是最持久的计算格式。你可以用 Emacs 轻松地打开 1970 年的文本文件。然而对于办公应用程序却并非如此。同时文本文件要比 Office 应用程序数据文件小得多，也要好的多。作为一个数码背包迷，作为一个在脑子里一闪而过就会做很多小笔记的人，拥有一个简单、轻便、永久、随时可用的东西对我来说很重要。 + +如果你准备尝试 Emacs，请继续阅读！下面的部分不会取代完整的教程，但是在完成阅读时，就可以操作了。 + +### 学会驾驭 Emacs —— 一个专业的配置 + +所有这些强大、精神上的平静和安宁的代价是，Emacs 有一个陡峭的学习曲线，它的一切都与你以前所习惯的不同。一开始，这会让你觉得你是在浪费时间在一个过时和奇怪的应用程序上，就好像现代世界已经过去了。这有点像你只开过车，却要你去学骑自行车[7][13]。 + +### 该选哪个 Emacs + +我用的是 GNU 中 OS X 和 Windows 的通用版本的 Emacs。你可以在 [][34][http://emacsformacos.com/][35] 获取 OS X 版本，在[][36][http://www.gnu.org/software/emacs/][37]获取 Windows 版本。市面上还有很多其他版本，尤其是 Mac 版本，但我发现，要做一些功能强大的东西（包括 `Lisp` 和许多模式），学习曲线要比实际操作低得多。下载，然后我们就可以开始了[8][14]！ + +### 首先，学会浏览 + +在本文中，我将约定 Emacs 中的键和组合。`C` 表示 `Control` 键，`M` 表示 `meta`（通常是 `Alt` 或 `Option` 键），以及用于组合键的连字符。因此，`C-h t` 表示同时按下 `Control` 和 `h` 键，然后释放，再按下 `t`。这个组快捷键会指向一个教程，这是你首先要做的一件事。 + +不要使用方向键或鼠标。它们可以工作，但是你应该给自己一周的时间来使用 Emacs 教程中的原生命令。一旦你这些命令变为了肌肉记忆，你可能就会乐在其中，无论到哪里，你都会非常想念它们。Emacs 教程在介绍它们方面做得很好，但是我将进行总结，所以您不需要阅读全部内容。最无聊的是，不用方向键，用 `C-b` 向前移动，用 `C-f` 向后移动，上一行用 `C-p`，下一行用 `C-n`。你可能会想：“我用方向键就很好，为什么还要这样做？” 有几个原因。首先，你不需要从主键盘区将你的手移开。第二，使用 `Alt`（或用 Emacs 的说法 `Meta`)键来向前或向后移动一个单词。显而易见这样更方便。第三，如果想重复某个命令，可以在命令前面加上一个数字。在编辑文档时，我经常使用这种方法，通过估计向前多少个单词或向上或线下移动多少行，然后按下 `C-9 C-p` 或 `M-5 M-b` 之类的快捷键。其他真正重要的浏览命令基于开头用 `a` 和结尾用 `e`。在行中使用 `C-a|e`，在句中使用 `M-a|e`。为了让句中的命令正常工作，需要在句号后增加两个空格，这同时提供了一个有用的特性，并消除了脑中的[希伯列][38]。如果需要将文档导出到单个空间[发布环境][39]，可以编写一个宏来执行此操作。 + +Emacs 附带的教程很值得去看。对于真正缺乏耐心的人，我将介绍一些重要的命令，但那个教程非常有用。记住：用 `C-h t` 进入教程。 + +### 学会复制和粘贴 + +你可以叫 Emacs 设为 `CUA` 模式，这将会以熟悉的方式工作来操作复制粘贴，但是原生的 Emacs 方法更好，而且你一旦学会了它，就很容易。你可以使用 `Shift` 这样的浏览命令来标记区域（如选择）。所以 `C-F` 是选中管标前的一个字符，等等。亦可以用 `M-w` 来复制，用 `C-w` 剪切，然后用 `C-y` 粘贴。这些实际上叫做删除和召回，但它非常类似于剪切和粘贴。在删除的环中有些小技巧，但是现在，你只需要关注剪切、复制和粘贴。如果你在这开始摸索， `C-x u` 是撤销。 + +### 下一步，学会用 `Ido` 模式 + +相信我，`Ido` 会让文件的工作变得很简单。通常，你在 Emacs 中处理文件不需要使用一个单独分开的查找或文件资源管理器的窗口。相反的，你可以用编辑器的命令来创建、打开和保存文件。如果没有 `Ido` 的话，这将有点麻烦，所以我建议你在学习其他之前安装好它。 `Ido` 是 Emacs 的 22 版时开发出来的，但是需要对你的 `.emacs` 文件做一些调整，来确保它一直开启着。这是个配置环境的好理由。 + +Emacs 中的大多数功能都表现在模式上。要安装制定的模式，需要做两件事。嗯，一开始你需要做一些额外的事情，但这些只需要做一次，然后再做这两件事。那么，额外的事情是你需要一个单独的位置来放置所有 `Emacs Lisp` 文件，并且你需要告诉 Emacs 这个位置在哪。我建议你在 Dropbox 上创建一个单独的目录，那是你 Emacs 主目录。在这里，你需要创建一个 `.emacs` 文件和 `.emacs.d` 目录。在 `.emacs.d` 目录下，创建一个 `lisp` 的目录。就像这样: + +``` +home +| ++.emacs +| +-.emacs.d + | + -lisp +``` + +你可以将那些像模式的 `.el` 文件放到 `home/.emacs.d/lis` 目录下，然后在你的 `.emacs` 文件中添加以下代码来指明该路径： + +`(add-to-list 'load-path "~/.emacs.d/lisp/")` + +`Ido` 模式是 Emacs 自带的，所以你不需要在你的 `lisp` 目录中放 `.el` 文件，但你仍然需要添加上面代码，因为下面的介绍会使用到它. + +### 符号链接是你的好伙伴 + +等等，这里写的 `.emacs` 和 `.emacs.d` 都是存放在你的主目录下，但我们把他们放到了 Dropbox 的某些愚蠢的文件夹！对，这就让你的环境在任何地方都很容易使用。把所有东西都保存在 Dropbox 上，并链接到 `.emacs` 和 `.emacs.d`，以及主目录 `~`。在 OS X 上，使用 `ln -s` 命令非常简单，但在 Windows 上却很麻烦。幸运的是，Emacs 提供了一种简单的方法来替代 Windows 上的符号链接，Windows 的 `HOME` 环境变量。转到 Windows 的环境变量（Windows 10,你可以按 Windows 键然后输入 “环境变量” 来搜索，这是 Windows 10 最好的一部分了)，在你的帐户下创建一个指向你在 Dropbox 中 Emacs 的文件家的 `HOME` 环境变量。如果你想方便地浏览 Dropbox 之外的本地文件，你可能想在你的实际主目录下建立一个到 Dropbox 下 Emacs 主目录的符号链接。 + +至此，你已经完成了在任意机器上指向 Emacs 配置和配置文件所需的技巧。如果你买了一台新电脑，或者用别人的电脑一小时或一天，你就得到了你的整个工作环境。第一次做这个似乎有点困难，但是一旦你知道你在做什么，就只需要10分钟(最多)。 + +但我们现在是在配置 `Ido`…… + +按下 `C-x` `C-f` 然后输入 `~/.emacs RET RET` 来创建 `.emacs` 文件，将下面几行添加进去: + +``` +;; set up ido mode +(require `ido) +(setq ido-enable-flex-matching t) +(setq ido-everywhere t) +(ido-mode 1) +``` + +在 `.emacs` 窗口开着的时候，执行 `M-x evaluate-buffer` 命令。如果某处弄错了的话，将得到一个错误，或者你将得到 `Ido`。`Ido` 改变了在 `minibuffer` 中操作文件操方式。有一篇比较好的文档，但是我也会指出一些技巧。有效地使用 `~/`；你可以在 `minibuffer` 的任何地方输入 `~/`，它就会跳转到主目录。这就意味着，你应该让你的大部分东西就近的放在主目录下。我用 `~/org` 目录来保存所有非代码的东西，用 `~/code` 保存代码。一旦你进入到正确的目录，通常会拥有一组具有不同扩展名的文件，特别是当你使用 `Org` 模式并从中发布的话。你可以输入 `period` 和想要的扩展名，无论你的在文件名的什么位置，`Ido` 都会将选择限制在具有该扩展名的文件中。例如，我在 `Org` 模式下写这篇博客，所以该文件是: + +`~/org/blog/emacs.org` + +我偶尔也会用 `Org` 模式发布成 HTML 格式，所以我将在同一目录下得到 `emacs.html` 文件。当我想打开 `Org` 文件时，我会输入: + +`C-x C-f ~/o[RET]/bl[RET].or[RET]` + +其中 `[RET]` 是我使用 `Ido` 模式的自动补全而按下的回车键。所以，这只需要按 12 个键，如果你习惯了的话， 这将比打开查找或文件资源管理器再用鼠标点要节省 _很_ 多时间。 `Ido` 模式很有用， 这真的是操作 Emacs 的一种实用的模式。下面让我们去探索一些其他对完成工作很有帮助的模式吧。 + +### 字体及风格 + +我推荐在 Emacs 中使用很棒的字体系列。它们可以使用不同的括号、0和其他字符进行自定义。你可以在字体文件本身中构建额外的行间距。我推荐 1\.5 倍的行间距，并在代码和数据中使用它们适应比例的字体。写作中我用 `Serif` 字体，它有一种紧凑但时髦的感觉。你可以在 [http://input.fontbureau.com/][40] 上找到它们，在那里你可以根据自己的喜好进行定制。你可以使用 Emacs 中的菜单手动设置字体，但这会将代码保存到你的 `.emacs` 文件中，如果您使用多个设备，您可能需要一些不同的设置。我我将我的 `.emacs` 设置位根据使用的机器的名称，并配置适当的屏幕机字体。代码如下: + +``` +;; set up fonts for different OSes. OSX toggles to full screen. +(setq myfont "InputSerif") +(cond +((string-equal system-name "Sampo.local") + (set-face-attribute 'default nil :font myfont :height 144) + (toggle-frame-fullscreen)) +((string-equal system-name "Morpheus.local") + (set-face-attribute 'default nil :font myfont :height 144)) +((string-equal system-name "ILMARINEN") + (set-face-attribute 'default nil :font myfont :height 106)) +((string-equal system-name "UKKO") + (set-face-attribute 'default nil :font myfont :height 104))) +``` + +您应该将你的 Emacs 副本中 `system-name` 的值替换成你使用命令 `(system-name)` 得到的值。注意，在 Sampo （我的 MacBook）上，我还将 Emacs 设置为全屏。我也想在 Windows 实现这个，但是 Windows 和 Emacs 并不真正喜欢对方，当我尝试这个时，它总是不稳定。相反，我只是在启动后手动全屏。 + +我还建议去掉 Emacs 中在 90 年代获得的难看的工具栏，当时最酷的事情是在应用程序中使用工具栏。我还去掉了一些其他的 `chrome`，这样我就有了一个简单、高效的界面。把这些加到你的 `.emacs` 的文件中，来去掉工具栏和滚动条，但要保留菜单 （在 OS X 上，它将被隐藏，除非你将鼠标到屏幕顶部）: + +``` +(if (fboundp 'scroll-bar-mode) (scroll-bar-mode -1)) +(if (fboundp 'tool-bar-mode) (tool-bar-mode -1)) +(if (fboundp 'menu-bar-mode) (menu-bar-mode 1)) +``` + +### Org 模式 + +我基本上 `Org` 模式下处理工作的。它是我创作文档、记笔记、列任务清单以及 90% 其他工作的首选环境。`Org` 最初是由一个在会议中使用笔记本电脑的家伙构想出来的，它是笔记和待办事项列表的组合工具。我反对在会议中使用笔记本电脑，自己也不使用，所以我的用法与他的有些不同。对我来说，`Org` 主要是一种处理结构中内容的方式。在 `Org` 模式中有标题和副标题等，它们的作用就像一个大纲。`Org` 允许你展开或隐藏文本内容，还可以重新排列文本。这非常很符合我的想法，而且我发现用这种方式使用它是一种乐趣。 + +`Org` 模式也有很多让生活愉快的小功能。例如，脚注处理非常好，`LaTeX/PDF` 输出也很好。`Org` 能够根据所有文档中的待办事项生成议程，并能很好地将它们与日期/时间联系起来。我不把它用在任何形式的外部任务上，这些任务都是在一个共享的日历上处理的，但是在创建事物和跟踪我未来需要创建的东西时，它是无价的。安装它，你只要将 `org-mode.el` 放到你的 `lisp` 目录下，然后再在你的 `.emacs` 文件中添加如下代码，如果你想要它基于文档的结构进行缩进并在打开时全部展开的话: + +``` +;; set up org mode +(setq org-startup-indented t) +(setq org-startup-folded "showall") +(setq org-directory "~/org") +``` + +最后一行是让 `Org` 知道在哪里查找要包含在议程和其他事情中的文件。我把 `Org` 保存在我的主目录中，也就是说，像前面介绍的一样，它是 Dropbox 目录的一个符号链接。 + +我有一个总是在缓冲区中打开的 `stuff.org` 文件。我把它当作记事本。`Org` 使得提取待办事项和有期限的事情变得很容易。当你在内联 `Lisp` 代码并在需要计算它时，它特别有用。拥有包含内容的代码非常方便。同样，你可以使用 Emacs 访问实际的计算机，这是一种解放。 + +#### 用 `Org` 模式进行发布 + +我关心的是文档的外观和格式。我我刚开始工作时是个设计师，而且我认为信息可以，也应该表现得清晰和美丽。`Org` 对将 `LaTeX` 生成 PDF 支持的很好, `LaTeX` 有自己的学习曲线，但是做简单的事情非常简单。 + +如果你想使用字体和样式，而不是典型的 `LaTeX` 字体和样式，你需要做些事。首先，你要用到 `XeLaTeX`，这样就可以使用普通的系统字体，而不是 `LaTeX` 的特殊字体。接下来，您需要将一下代码添加到 `.emacs` 中： + +``` +(setq org-latex-pdf-process + '("xelatex -interaction nonstopmode %f" + "xelatex -interaction nonstopmode %f")) +``` + +我把这个放在 `.emacs` 中 `Org` 配置部分的末尾来保持整洁。这让你在从 `Org` 发布时使用更多格式化选项。例如，我经常使用: + +``` +#+LaTeX_HEADER: \usepackage{fontspec} +#+LATEX_HEADER: \setmonofont[Scale=0.9]{Input Mono} +#+LATEX_HEADER: \setromanfont{Maison Neue} +#+LATEX_HEADER: \linespread{1.5} +#+LATEX_HEADER: \usepackage[margin=1.25in]{geometry} + +#+TITLE: Document Title Here +``` + +这些都可以在你的 `.org` 文件中找到。我们的公司规定的正文字体是 `Maison Neue`，但你也可以在这写上任何适当的东西。我强烈反对使用 `Maison Neue`。它是一种糟糕的字体，任何人都不应该使用它。 + +这个文件是一个使用该配置输出为 PDF 的实例。这就是开箱即用的 `LaTeX` 一样。在我看来这还不错，但是字体很无聊，而且有点奇怪。此外，如果你使用标准格式，人们会认为他们正在阅读的东西是或假装是一篇学术论文。别怪我没提醒你。 + +### `Ace Jump` 模式 + +如果你想使用的话，这是个辅助而不是主要功能。它的工作原理有点像 Jef Raskin 的 `Leap` 功能[9][15]。 按下 `C-c` `C-SPC`，然后输入要跳转到单词的第一个字母。它会高亮显示所有以该字母开头的单词，并将其替换为字母表中的字母。您只需键入所需位置的字母，光标就会跳转到该位置。我自己经常用这个作为导航键或搜索。将 `.el` 文件下到你的 `Lisp` 目录下，并在 `.emacs` 文件添加如下代码: + +``` +;; set up ace-jump-mode +(add-to-list 'load-path "which-folder-ace-jump-mode-file-in/") +(require 'ace-jump-mode) +(define-key global-map (kbd "C-c C-SPC" ) 'ace-jump-mode) +``` + +### 更多 + +这篇文章已经够详细了，你能在其中的到你所想要的。我很想了解除编程（或编程）之外你对 Emacs 的使用，以及这是否有用。在我使用 Emacs 的过程中，可能存在一些自作聪明的想法，如果你能指出它们，我将感激不尽。之后，我可能会写一些更新来引入其他特性或模式。我很确定我将会向你展示如何在 Emacs 和 `Ludwig` 模式下使用 `Fugue`，因为我会将它发展成比代码突出显示更有用的东西。把你的想法发到 [@fugueHQ][41] 上。 + +* * * + +#### 附注 + +1. [^][16] If you are now a PHB of some sort, but were never technical, Emacs likely isn’t for you. There may be a handful of folks for whom Emacs will form a path into the more technical aspects of computing, but this is probably a small population. It’s helpful to know how to use a Unix or Windows terminal, to have edited a dotfile or two, and to have written some code at some point in your life for Emacs to make much sense. + +2. [^][17] [][18][http://archive.wired.com/wired/archive/2.08/tufte.html][19] + +3. [^][20] I mainly use this to perform calculations while writing. For example, I was writing an offer letter to a new employee and wanted to calculate how many options to include in the offer. Since I have a variable defined in my `.emacs` for outstanding-shares, I can simply type `M-: (* .001 outstanding-shares)`and get a tenth of a point without opening a calculator or spreadsheet. I keep _lots_ of numbers in variables like this so I can avoid context switching. + +4. [^][21] The missing piece of this is the web. There is an Emacs web browser called eww that will allow you to browse in Emacs. I actually use this, as it is both a great ad-blocker and removes most of the poor choices in readability from the web designer's hands. It's a bit like Reading Mode in Safari. Unfortunately, most websites have lots of annoying cruft and navigation that translates poorly into text. + +5. [^][22] Usability is often confused with learnability. Learnability is how difficult it is to learn a tool. Usability is how useful the tool is. Often, these are at odds, such as with the mouse and menus. Menus are highly learnable, but have poor usability, so there have been keyboard shortcuts from the earliest days. Raskin was right on many points where he was ignored about GUIs in general. Now, OSes are putting things like decent search onto a keyboard shortcut. On OS X and Windows, my default method of navigation is search. Ubuntu's search is badly broken, as is the rest of its GUI. + +6. [^][23] AWS S3 has effectively solved file storage for as long as we have the Internet. Trillions of objects are stored in S3 and they've never lost one of them. Most every service out there that offers cloud storage is built on S3 or imitates it. No one has the scale of S3, so I keep important stuff there, via Dropbox. + +7. [^][24] By now, you might be thinking "what is it with this guy and bicycles?" ... I love them on every level. They are the most mechanically efficient form of transportation ever invented. They can be objects of real beauty. And, with some care, they can last a lifetime. I had Rivendell Bicycle Works build a frame for me back in 2001 and it still makes me happy every time I look at it. Bicycles and UNIX are the two best inventions I've interacted with. Well, they and Emacs. + +8. [^][25] This is not a tutorial for Emacs. It comes with one and it's excellent. I do walk through some of the things that I find most important to getting a useful Emacs setup, but this is not a replacement in any way. + +9. [^][26] Jef Raskin designed the Canon Cat computer in the 1980s after falling out with Steve Jobs on the Macintosh project, which he originally led. The Cat had a document-centric interface (as all computers should) and used the keyboard in innovative ways that you can now imitate with Emacs. If I could have a modern, powerful Cat with a giant high-res screen and Unix underneath, I'd trade my Mac for it right away. [][27][https://youtu.be/o_TlE_U_X3c?t=19s][28] + +-------------------------------------------------------------------------------- + +via: https://blog.fugue.co/2015-11-11-guide-to-emacs.html + +作者：[Josh Stella ][a] +译者：[oneforalone](https://github.com/oneforalone) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]:https://blog.fugue.co/authors/josh.html +[1]:https://blog.fugue.co/2013-10-16-vpc-on-aws-part3.html +[2]:https://blog.fugue.co/2013-10-02-vpc-on-aws-part2.html +[3]:http://ww2.fugue.co/2017-05-25_OS_AR_GartnerCoolVendor2017_01-LP-Registration.html +[4]:https://blog.fugue.co/authors/josh.html +[5]:https://twitter.com/joshstella +[6]:https://www.youtube.com/watch?v=khJQgRLKMU0 +[7]:https://blog.fugue.co/2015-11-11-guide-to-emacs.html?utm_source=wanqu.co&utm_campaign=Wanqu+Daily&utm_medium=website#phb +[8]:https://blog.fugue.co/2015-11-11-guide-to-emacs.html?utm_source=wanqu.co&utm_campaign=Wanqu+Daily&utm_medium=website#tufte +[9]:https://blog.fugue.co/2015-11-11-guide-to-emacs.html?utm_source=wanqu.co&utm_campaign=Wanqu+Daily&utm_medium=website#interpreter +[10]:https://blog.fugue.co/2015-11-11-guide-to-emacs.html?utm_source=wanqu.co&utm_campaign=Wanqu+Daily&utm_medium=website#eww +[11]:https://blog.fugue.co/2015-11-11-guide-to-emacs.html?utm_source=wanqu.co&utm_campaign=Wanqu+Daily&utm_medium=website#usability +[12]:https://blog.fugue.co/2015-11-11-guide-to-emacs.html?utm_source=wanqu.co&utm_campaign=Wanqu+Daily&utm_medium=website#s3 +[13]:https://blog.fugue.co/2015-11-11-guide-to-emacs.html?utm_source=wanqu.co&utm_campaign=Wanqu+Daily&utm_medium=website#bicycles +[14]:https://blog.fugue.co/2015-11-11-guide-to-emacs.html?utm_source=wanqu.co&utm_campaign=Wanqu+Daily&utm_medium=website#nottutorial +[15]:https://blog.fugue.co/2015-11-11-guide-to-emacs.html?utm_source=wanqu.co&utm_campaign=Wanqu+Daily&utm_medium=website#canoncat +[16]:https://blog.fugue.co/2015-11-11-guide-to-emacs.html?utm_source=wanqu.co&utm_campaign=Wanqu+Daily&utm_medium=website#phbOrigin +[17]:https://blog.fugue.co/2015-11-11-guide-to-emacs.html?utm_source=wanqu.co&utm_campaign=Wanqu+Daily&utm_medium=website#tufteOrigin +[18]:http://archive.wired.com/wired/archive/2.08/tufte.html +[19]:http://archive.wired.com/wired/archive/2.08/tufte.html +[20]:https://blog.fugue.co/2015-11-11-guide-to-emacs.html?utm_source=wanqu.co&utm_campaign=Wanqu+Daily&utm_medium=website#interpreterOrigin +[21]:https://blog.fugue.co/2015-11-11-guide-to-emacs.html?utm_source=wanqu.co&utm_campaign=Wanqu+Daily&utm_medium=website#ewwOrigin +[22]:https://blog.fugue.co/2015-11-11-guide-to-emacs.html?utm_source=wanqu.co&utm_campaign=Wanqu+Daily&utm_medium=website#usabilityOrigin +[23]:https://blog.fugue.co/2015-11-11-guide-to-emacs.html?utm_source=wanqu.co&utm_campaign=Wanqu+Daily&utm_medium=website#s3Origin +[24]:https://blog.fugue.co/2015-11-11-guide-to-emacs.html?utm_source=wanqu.co&utm_campaign=Wanqu+Daily&utm_medium=website#bicyclesOrigin +[25]:https://blog.fugue.co/2015-11-11-guide-to-emacs.html?utm_source=wanqu.co&utm_campaign=Wanqu+Daily&utm_medium=website#nottutorialOrigin +[26]:https://blog.fugue.co/2015-11-11-guide-to-emacs.html?utm_source=wanqu.co&utm_campaign=Wanqu+Daily&utm_medium=website#canoncatOrigin +[27]:https://youtu.be/o_TlE_U_X3c?t=19s +[28]:https://youtu.be/o_TlE_U_X3c?t=19s +[29]:https://blog.fugue.co/authors/josh.html +[30]:http://www.huffingtonpost.com/zachary-ehren/soma-isnt-a-drug-san-fran_b_987841.html +[31]:http://www.campagnolo.com/US/en +[32]:http://www.businessinsider.com/best-pointy-haired-boss-moments-from-dilbert-2013-10 +[33]:http://www.webopedia.com/TERM/I/interpreter.html +[34]:http://emacsformacosx.com/ +[35]:http://emacsformacosx.com/ +[36]:http://www.gnu.org/software/emacs/ +[37]:http://www.gnu.org/software/emacs/ +[38]:http://www.huffingtonpost.com/2015/05/29/two-spaces-after-period-debate_n_7455660.html +[39]:http://practicaltypography.com/one-space-between-sentences.html +[40]:http://input.fontbureau.com/ +[41]:https://twitter.com/fugueHQ diff --git a/translated/tech/20180228 Emacs -2- Introducing org-mode.md b/translated/tech/20180228 Emacs -2- Introducing org-mode.md new file mode 100644 index 0000000000..db22d1449c --- /dev/null +++ b/translated/tech/20180228 Emacs -2- Introducing org-mode.md @@ -0,0 +1,177 @@ +[#]: collector: (lujun9972) +[#]: translator: (oneforalone) +[#]: reviewer: ( ) +[#]: publisher: ( ) +[#]: subject: (Emacs #2: Introducing org-mode) +[#]: via: (https://changelog.complete.org/archives/9865-emacs-2-introducing-org-mode) +[#]: author: (John Goerzen http://changelog.complete.org/archives/author/jgoerzen) +[#]: url: ( ) + +Emacs 系列（二）：`Org` 模式介绍 +====== + +在我 Emacs 系列中的[第一片文章][1]里，我介绍了我在用了几十年的 vim 后转向了 Emacs，`Org` 模式就是我为什么这样做的原因。 + +`Org` 模式的精简和高效真的震惊了我，它真的是个“杀手”应用。 + +**所以，`Org`模式到底是什么呢？** + +这是我昨天写的： + +> 它是一个组织信息的平台，它的主页上这样写着：“一切都是纯文本：`Org` 模式用于记笔记、维护待办事项列表、计划项目和使用快速有效的纯文本系统编写文档。” + +这是事实，但并不是很准确。`Org` 模式是一个你用来组织事务的小工具。它有一些非常合理的默认设置，但也允许你自己定制。 + +主要突出在这几件事上： + + * **维护待办事项列表** : 项目可以分散在 `Org` 文件中，包含附件，有标签，截止日期，时间表。有一个方便的“日程”视图，显示需要做什么。项目也可以重复。 + * **编写文档** : `Org` 模式有个特殊的功能来生成 HTML、LaTeX、 幻灯片（用 LaTeX beamer）和其他所有的格式。它也支持直接在缓冲区中运行和编写几乎任何一种 Emacs 所支持的的语言。如果你想要深入了解这项功能的话，参阅[开发者文档][2]。官网给出的[文档][3]完全不对。 + * **记笔记** : 对，它也能做笔记。通过全文所搜，文件的交叉引用（类似 wiki），UUID，甚至可以与其他的系统进行交互（通过信息 ID 与 mu4e 交互， 通过 ERC 的日志等等……） + +**开始** + +我强烈建议去阅读 [Carsten Dominik 写的一篇很棒的关于 `Org` 模式的 Google 讲话][4]。那篇文章真的很赞。 + +Emacs 中自带了 `Org` 模式，但如果你想要个比较新的版本的话，Debian 用户可以使用命令 `apt-get install org-mode` 来更新，或者使用 Emacs 的包管理系统命令 `M-x package-install RET org-mode RET`。 + +现在，你可能需要阅读一下 `Org` 模式的精简版教程中的[导读部分][5]，特别注意，你要设置下[启动部分][6]中提到的那些键的绑定。 + +**一份好的教程** + +我会给出一些好的教程和介绍的链接，但这篇文章不会是一篇教程。特别是在本文末尾，有两个很不错的视频链接。 + +**我的一些配置** + +我将在这里记录下一些我的配置并介绍它的作用。你没有必要每行每句将它拷贝到你的配置中——这只是一个参考，告诉你哪些可以配置，要怎么在手册中查找，或许只是一个“我现在该怎么做”的参考。 + +首先，我将 Emacs 的编码默认设置为 UTF-8。 +``` +(prefer-coding-system 'utf-8) (set-language-environment "UTF-8") +``` + +`Org` 模式中可以打开 URL。默认的，它会在 Firefox 中打开，但我喜欢用 Chromium。 +``` +(setq browse-url-browser-function 'browse-url-chromium) +``` + +我把基本的键的绑定和设为教程里的一样，再加上 `M-RET` 的操作的配置。 + +``` +(global-set-key "\C-cl" 'org-store-link) +(global-set-key "\C-ca" 'org-agenda) +(global-set-key "\C-cc" 'org-capture) +(global-set-key "\C-cb" 'org-iswitchb) + +(setq org-M-RET-may-split-line nil) +``` + + +**捕获配置** + +我可以在 Emacs 的任何模式中按 `C-c c`，按下后它就会[帮我捕获某些事][7]，其中包括一个指向我正在处理事务的链接。 + +你可以通过定义[捕获模板][8]来配置它。我将保存两个日志文件，作为会议、电话等的通用记录。一个是私人用的，一个是办公用的。如果我按下 `C-c c j`,它就会帮我捕获为私人项. 下面包含 `%a` 的配置是表示我当前的位置（或是我使用 `C-c l` 保存的链接）的链接。 + +``` +(setq org-default-notes-file "~/org/tasks.org") +(setq org-capture-templates + '( + ("t" "Todo" entry (file+headline "inbox.org" "Tasks") + "* TODO %?\n %i\n %u\n %a") + ("n" "Note/Data" entry (file+headline "inbox.org" "Notes/Data") + "* %? \n %i\n %u\n %a") + ("j" "Journal" entry (file+datetree "~/org/journal.org") + "* %?\nEntered on %U\n %i\n %a") + ("J" "Work-Journal" entry (file+datetree "~/org/wjournal.org") + "* %?\nEntered on %U\n %i\n %a") + )) +(setq org-irc-link-to-logs t) +``` + +我喜欢通过 UUID 来建立链接，这让我在文件之间移动而不会破坏位置。当我要 `Org` 存储一个链接目标以便将来插入时，以下配置有助于生成 UUID。 + +``` +(require 'org-id) +(setq org-id-link-to-org-use-id 'create-if-interactive) +``` + +**议程配置** + +我喜欢将星期天作为一周的开始，当我将某件事标记为完成时，我也喜欢记下时间。 + +``` +(setq org-log-done 'time) +(setq org-agenda-start-on-weekday 0) +``` + +**文件归档配置** + +在这我将配置它， 让它知道在议程中该使用哪些文件，而且在纯文本的搜索中添加一点点小功能。我喜欢保留一个通用的文件夹(我可以从其中移动或“重新归档”内容)，然后将个人和工作项的任务、日志和知识库分开。 + +``` + (setq org-agenda-files (list "~/org/inbox.org" + "~/org/email.org" + "~/org/tasks.org" + "~/org/wtasks.org" + "~/org/journal.org" + "~/org/wjournal.org" + "~/org/kb.org" + "~/org/wkb.org" + )) + (setq org-agenda-text-search-extra-files + (list "~/org/someday.org" + "~/org/config.org" + )) + + (setq org-refile-targets '((nil :maxlevel . 2) + (org-agenda-files :maxlevel . 2) + ("~/org/someday.org" :maxlevel . 2) + ("~/org/templates.org" :maxlevel . 2) + ) + ) +(setq org-outline-path-complete-in-steps nil) ; Refile in a single go +(setq org-refile-use-outline-path 'file) +``` + +**外观配置** + +我喜欢一个较漂亮的的屏幕。在你开始习惯 `Org` 之后，你可以试试这个。 + +``` +(require 'org-bullets) +(add-hook 'org-mode-hook + (lambda () + (org-bullets-mode t))) +(setq org-ellipsis "⤵") +``` + +**下一篇** + +希望这篇文章展示了 `Org` 模式的一些功能。接下来，我将介绍如何定制 `TODO` 关键字和标记、归档旧任务、将电子邮件转发到 `Org` 模式，以及如何使用 `git` 在不同电脑之间进行同步。 + +你也可以查看[本系列的所有文章列表][9]。 + + + +-------------------------------------------------------------------------------- + +via: https://changelog.complete.org/archives/9865-emacs-2-introducing-org-mode + +作者：[John Goerzen][a] +选题：[lujun9972][b] +译者：[oneforalone](https://github.com/oneforalone) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]: http://changelog.complete.org/archives/author/jgoerzen +[b]: https://github.com/lujun9972 +[1]: https://changelog.complete.org/archives/9861-emacs-1-ditching-a-bunch-of-stuff-and-moving-to-emacs-and-org-mode +[2]: http://www.howardism.org/Technical/Emacs/literate-devops.html +[3]: https://orgmode.org/worg/ +[4]: https://www.youtube.com/watch?v=oJTwQvgfgMM +[5]: https://orgmode.org/guide/Introduction.html#Introduction +[6]: https://orgmode.org/guide/Activation.html#Activation +[7]: https://orgmode.org/guide/Capture.html#Capture +[8]: https://orgmode.org/guide/Capture-templates.html#Capture-templates +[9]: https://changelog.complete.org/archives/tag/emacs2018 diff --git a/translated/tech/20180302 Emacs -3- More on org-mode.md b/translated/tech/20180302 Emacs -3- More on org-mode.md new file mode 100644 index 0000000000..acfba8a1ed --- /dev/null +++ b/translated/tech/20180302 Emacs -3- More on org-mode.md @@ -0,0 +1,131 @@ +[#]: collector: (lujun9972) +[#]: translator: (oneforalone) +[#]: reviewer: ( ) +[#]: publisher: ( ) +[#]: subject: (Emacs #3: More on org-mode) +[#]: via: (https://changelog.complete.org/archives/9877-emacs-3-more-on-org-mode) +[#]: author: (John Goerzen http://changelog.complete.org/archives/author/jgoerzen) +[#]: url: ( ) + +Emacs 系列（三）： `Org` 模式的补充 +====== + +这是 [Emacs 和 `Org` 模式系列][1]的第三篇。 + +**Todo 的跟进及关键字** + +当你使用 `Org` 模式来跟进的的 TODO 时，它有多种状态。你可以用 `C-c C-t` 来快速切换状态。我将它设为这样： + +``` +(setq org-todo-keywords '( + (sequence "TODO(t!)" "NEXT(n!)" "STARTED(a!)" "WAIT(w@/!)" "OTHERS(o!)" "|" "DONE(d)" "CANCELLED(c)") +)) +``` + +在这里，我设置了一个任务未完成的五种状态：`TODO`、`NEXT`、`STARTED`、`WAIT` 及 `OTHERS`。每一个状态都单个字的快捷键（t，n，a 等）。这些符号之后的状态被认为是“完成”的状态。我有两个“完成”状态：`DONE`（已经完成）及 `CANCELLED`（还没完成，但由于其它的原因无法完成）。 + +`!` 的含义是记录某项更改为状态的时间。我不把这个添加到完成的状态，是因为它们已经被记录了。`@` 符号表示带理由的提示，所以当切换到 `WAIT` 时，`Org` 会问我为什么，并将这个添加到笔记中。 + +以下是项目状态发生变化的例子： + +``` +** DONE This is a test + CLOSED: [2018-03-02 Fri 03:05] + + - State "DONE" from "WAIT" [2018-03-02 Fri 03:05] + - State "WAIT" from "TODO" [2018-03-02 Fri 03:05] \\ + waiting for pigs to fly + - State "TODO" from "NEXT" [2018-03-02 Fri 03:05] + - State "NEXT" from "TODO" [2018-03-02 Fri 03:05] +``` + +在这里，最新的项目在最上面。 + +**议程模式，日程及期限** + +当你处在一个待办项时，`C-c C-s` 或 `C-c C-d` 可以为其设置相应的日程或期限。这些都是在议程模式中的功能。区别在于意图和表现。日程是你希望在某个时候完成的事情，而期限是在某个特定的时间应该完成的事情。默认情况下，议程视图将在项目的截止日期前提醒你。 + +在此过程中，[议程视图][3]将显示即将出现的项目，提供了一种基于纯文本或标记搜索项目的方法，甚至可以进行跨多个文件处理项目的批量操作。我在本系列的[第 2 部分][4]中介绍了为议程模式配置。 + +**标签** + +`Org` 模式当然也支持标签了。你可以通过 `C-c C-q` 快速的建立标签。 + +你可能会想为一些常用的标签设置快捷键。就像这样: + +``` +(setq org-tag-persistent-alist +'(("@phone" . ?p) +("@computer" . ?c) +("@websurfing" . ?w) +("@errands" . ?e) +("@outdoors" . ?o) +("MIT" . ?m) +("BIGROCK" . ?b) +("CONTACTS" . ?C) +("INBOX" . ?i) +)) +``` + +你还可以根据每个文件向该列表添加标记，也可以根据每个文件为某些内容设置标记。我就在我的 `inbox.org` 和 `email.org` 文件中设置了一个 `INBOX` 的标签。然后我可以每天从日程视图中查看所有标记为 `INBOX` 的项目，像将它们重新归档到其他文件中的简单操作将让它们去掉 `INBOX` 标记。 + +**重新归档** + +“重新归档”就是在文件中或其他地方移动。它是使用标来题完成。`C-c C-w` 就是做这个的。我设置成这样: + +``` +(setq org-outline-path-complete-in-steps nil) ; Refile in a single go +(setq org-refile-use-outline-path 'file) +``` + +**归档分类** + +一段时间后，你的文件就会被已经完成的事情弄得乱七八糟。`Org` 模式有一个[归档][6]特性，可以将主 `.org` 文件移到其他文件中，以备将来参考。如果你在 `git` 或其他软件中 有 `Org` 文件，你可能希望删除这些其他文件，因为无论如何都会在历史中拥有这些文件，但是我发现它们对于 `grepping` 和搜索非常方便。 + +我会定期检查并归档文件中的所有内容。基于 [stackoverflow 的讨论][7]，我有以下代码: + +``` +(defun org-archive-done-tasks () + (interactive) + (org-map-entries + (lambda () + (org-archive-subtree) + (setq org-map-continue-from (outline-previous-heading))) + "/DONE" 'file) + (org-map-entries + (lambda () + (org-archive-subtree) + (setq org-map-continue-from (outline-previous-heading))) + "/CANCELLED" 'file) +) +``` + +这基于[一个特定的答案][8]——你可以从评论那获得一些额外的提示。现在你可以运行 `M-x org-archive-done-tasks`，当前文件中所有标记为 `DONE` 或 `CANCELED` 的内容都将放到另一个文件中。 + +**下一篇** + +我将通过讨论在 `Org` 模式中自动接受邮件以及在不同的机子上同步来对 `Org` 模式进行总结。 + + + +-------------------------------------------------------------------------------- + +via: https://changelog.complete.org/archives/9877-emacs-3-more-on-org-mode + +作者：[John Goerzen][a] +选题：[lujun9972][b] +译者：[oneforalone](https://github.com/oneforalone) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]: http://changelog.complete.org/archives/author/jgoerzen +[b]: https://github.com/lujun9972 +[1]: https://changelog.complete.org/archives/tag/emacs2018 +[2]: https://orgmode.org/guide/TODO-Items.html#TODO-Items +[3]: https://orgmode.org/guide/Agenda-Views.html#Agenda-Views +[4]: https://changelog.complete.org/archives/9865-emacs-2-introducing-org-mode +[5]: https://orgmode.org/guide/Tags.html#Tags +[6]: https://orgmode.org/guide/Archiving.html#Archiving +[7]: https://stackoverflow.com/questions/6997387/how-to-archive-all-the-done-tasks-using-a-single-command +[8]: https://stackoverflow.com/a/27043756 diff --git a/translated/tech/20180523 How to dual-boot Linux and Windows.md b/translated/tech/20180523 How to dual-boot Linux and Windows.md new file mode 100644 index 0000000000..9047928ba6 --- /dev/null +++ b/translated/tech/20180523 How to dual-boot Linux and Windows.md @@ -0,0 +1,238 @@ +如何实现 Linux + Windows 双系统启动 +===== + + + +尽管 Linux 是一个有着广泛的硬件和软件支持的操作系统，但事实上有时你仍需要使用 Windows，也许是因为有些不能在 Linux 下运行的重要软件。但幸运地是， 双启动 Windows 和 Linux 是很简单的—在这篇文章中我将会向你展示如何实现 Windows 10 + Ubuntu 18.04 双系统启动。 + +在你开始之前，确保你已经备份了你的电脑文件。 虽然设置双启动过程不是非常复杂，但意外有可能仍会发生。所以花一点时间来备份你的重要文件以防混沌理论发挥作用。除了备份你的文件之外，考虑制作一份备份镜像也是个不错的选择，虽然这不是必需的且会变成一个更高级的过程。 + +### 要求 + +为了开始，你将需要以下5项东西： + +#### 1\. 两个 USB 闪存盘（或者 DVD-Rs） + +我推荐用 USB 闪存盘来安装 Windows 和 Ubuntu，因为他们比 DVDs 更快。这通常是毋庸置疑的， 但是创建一个可启动的介质会抹除闪存盘上的一切东西。因此，确保闪存盘是空的或者其包含的文件是你不再需要的。 + +如果你的电脑不支持从 USB 启动，你可以创建 DVD 介质来代替。不幸的是， 因为没有两台电脑似乎有相同的 DVD 烧录软件，所以我无法引导这一过程。 然而，如果你的 DVD 烧录软件有从一个 ISO 镜像中烧录的选项，这个选项是你需要的。 + +#### 2\. 一份 Windows 10 许可证 + +如果你的电脑已经安装 Windows 10，那么许可证将会被安装到你的电脑中，所以你不需要担心在安装过程中输入它。如果你购买的是零售版，你应该拥有一个需要在安装过程中输入的产品密钥。 + +#### 3\. Windows 10介质创建工具 + +下载并运行 Windows 10 [介质创建工具][1]。一旦你运行这个工具，它将会引导你完成在一个 USB 或者 DVD-R 上创建 Windows 安装介质的所需步骤。注意： 即使你已经安装了 Windows 10 。总之创建一个可引导的介质是一个不错的主意，万一刚好系统出错了且需要你重新安装。 + +#### 4\. Ubuntu 18.04 安装介质 + +下载 [Ubuntu 18.04][2] ISO 镜像。 + +#### 5\. Etcher 软件（用于制作一个可引导 Ubuntu 的 USB 驱动器) +用于为任何 Linux 发型版本创建可启动的介质的工具，我推荐 [Etcher][3]。Etcher 可以在三大主流操作系统（Linux，MacOS，和 Windows）上运行且不会让你覆盖当前操作系统的分区。 + +一旦你下载完成并运行 Etcher，点击选择镜像并指向你在步骤4中下载的 Ubuntu ISO 镜像， 接下来， 点击驱动器以选择你的闪存驱动器，然后点击 ` Flash!` 开始将闪存驱动器转化为一个 Ubuntu 安装器的过程。 (如果你正使用一个 DVD-R， 使用你电脑中的 DVD 烧录软件来完成此过程。) + +### 安装 Windows 和 Ubuntu + +你应该准备好了，此时，你应该完成以下操作： + + * 备份你重要的文件 + * 创建 Windows 安装介质 + * 创建 Ubuntu 安装介质 + + + +有两种方法可以进行安装。首先，如果你已经安装了 WIndows 10 ，你可以让 Ubuntu 安装程序调整分区大小，然后在空白区域上进行安装。或者，如果你尚未安装 Windows 10，你可以在安装过程中将它安装在一个更小的分区上（下面我将描述如何去做）。第二种方法是首选的且出错率较低。很有可能你不会遇到任何问题。但是手动安装 Windows 并给它一个更小的分区，然后再安装 Ubuntu 是最简单的方法。 + +如果你的电脑上已经安装了 Windows 10，那么请跳过以下的 Windows 安装说明并继续安装 Ubuntu。 + +#### 安装 Windows + +将创建的 Windows 安装介质插入你的电脑中并引导其启动。这如何做取决于你的电脑。但大多数有一个可以按下以启动启动菜单的快捷键。例如，在戴尔的电脑上就是 F12键。如果闪存盘并未作为一个选项显示，那么你可能需要重新启动你的电脑。有时候，只有在启动电脑前插入介质才能使其显示出来。如果看到类似‘’请按任意键以从安装介质中启动“的信息，请按下任意一个键。然后你应该会看到如下的界面。选择你的语言和键盘样式，然后单击`Next`。 + + +![Windows 安装][5] + + +点击`现在安装`启动 Windows 安装程序 + +在下一个屏幕上，它会询问你的产品密钥。如果因你的电脑在出厂时已经安装了 Windows 10 而没有密钥的话，请选择‘’我没有一个产品密钥”。一旦赶上更新，它会在安装完成后自动激活。如果你有一个产品密钥，输入密钥并单击`下一步`。 + + +![输入产品密钥][7] + + +选择你想要安装的 Windows 版本。如果你有一个零售版，标签（LCTT 译者注：类似于 CPU 型号 的 logo 贴标，）会告诉你你有什么版本。否则，它通常与计算机的附带文档放在一起。在大多数情况下，它要么是 Windows 10 家庭版 或者 Windows 10 专业版。大多数带有 家庭版的电脑都有一个简单的标签，上面写着"Windows 10",而专业版则有明确的标签。 + + +![选择 Windows 版本][10] + + +勾选复选框以接受许可协议，然后单击`下一步`。 + + +![接受许可协议][12] + + +在接受协议后，你有两种可用的安装选项。选择第二个选项`自定义：只安装 Windows （高级）`。 + + +![选择 Windows 的安装方式][14] + + +接下来应该会显示你当前的硬盘配置。 + + +![硬盘配置][16] + + +你的结果可能看起来和我的不一样。我以前从来没有用过这个硬盘，所以它是完全未分配的。你可能会看到你当前操作系统的一个或多个分区。 + +此时，你的电脑屏幕将显示未分配的整个磁盘。创建一个新的分区以继续安装。 + + +![创建一个新分区][18] + + +你可以看到我通过创建一个81920MB 大小的分区（接近 160GB 的一半）将驱动器分成了一半（或者说分得足够近）。给 Windows 至少 40GB，最好 64GB 或者更多。把剩下的硬盘留着不要分配，作为以后安装 Ubuntu 的分区 + +你的结果应该看起来像这样： + + +![保留未分配空间的分区][20] + + +确认分区看起来很好，然后单击`下一步`。现在将开始安装 Windows。 + + +![安装 Windows][22] + + +如果你的电脑成功地引导进入了 Windows 桌面环境，你就可以进入下一步了。 + +![Windows 桌面][24] + + +#### 安装 Ubuntu + +无论你是已经安装了 Windows，还是完成了上面的步骤，现在你已经安装了 Windows。现在用你之前创建的 Ubuntu 安装介质来引导进入 Ubuntu。继续插入安装介质并从中引导你的电脑，同样，启动引导菜单的快捷键因计算机型号而异，因此如果你不确定，请查阅你的文档。如果一切顺利的话，当安装介质加载完成之后，你将会看到以下界面： + + +![Ubuntu 安装欢迎屏幕][26] + + +在这里，你可以选择 `尝试 Ubuntu` 或者 `安装 Ubuntu`。现在不要安装，相反，点击 `尝试 Ubuntu`。当完成加载之后，你应该可以看到 Ubuntu 桌面。 + +![Ubuntu 桌面][28] + +通过单击`尝试 Ubuntu`,你已经选择在安装之前试用 Ubuntu。 在 Live 模式下，你可以试用 Ubuntu，确保在你安装之前一切正常。Ubuntu 能兼容大多数 PC 硬件，但最好提前测试一下。确保你可以访问互联网并可以正常播放音频和视频。登录 YouTube 播放视频是一次性完成所有这些工作的好方法。如果你需要连接到无线网络，请单击屏幕右上角的网络图标。在那里，你可以找到一个无线网络列表并连接到你的无线网络。 + +准备好之后，双击桌面上的 `安装 Ubuntu 18.04 LTS`图标启动安装程序。 + +选择要用于安装过程的语言，然后单击 `继续`。 + + +![选择 Ubuntu 的语言][30] + + +接下来，选择键盘布局。完成后选择后，单击`继续`。 + + +![选择 Ubuntu 的键盘][32] + +在下面的屏幕上有一些选项。一，你可以选择一个正常安装或最小化安装。对大多数人来说，普通安装是理想的。高级用户可能想要默认安装应用程序比较少的最小化安装。此外，你还可以选择下载更新以及是否包含第三方软件和驱动程序。我建议同时检查这两个方框。完成后，单击`继续`。 + + +![选择 Ubuntu 安装选项][34] + +下一个屏幕将询问你是要擦除磁盘还是设置双启动。由于你是双启动，因此请选择`安装 Ubuntu，与 Windows 10共存`，单击`现在安装`。 + + +![安装 Ubuntu，与 Windows 10共存][36] + + +可能会出现以下屏幕。如果你从头开始安装 Windows 并在磁盘上保留了未分区的空间， Ubuntu 将会自动在空白区域中自行设置分区，因此你将看不到此屏幕。如果你已经安装了 Windows 10 并且它占用了整个驱动器，则会出现此屏幕，并在顶部为你提供一个选择磁盘的选项。如果你只有一个磁盘，则可以选择从 Windows 窃取多少空间给 Ubuntu。你可以使用鼠标左右拖动中间的垂直线以从其中一个分区中拿走一些空间并给另一个分区，按照你自己想要的方式调整它，然后单击`现在安装`。 + + +![分配驱动器空间][38] + + +你应该会看到一个显示 Ubuntu 计划将要做什么的确认屏幕，如果一切正常，请单击`继续`。 + +![确认屏幕][39] + +Ubuntu 正在后台安装。不过，你仍需要进行一些配置。当 Ubuntu 试图找到你的位置时，你可以点击地图来缩小范围以确保你的时区和其他设置是正确的。 + +![选择地理位置][40] + +接下来，填写用户账户信息：你的姓名、计算机名、用户名和密码。完成后单击`继续`。 + +![账户设置][41] + +现在你就拥有它了，安装完成了。继续并重启你的电脑。 + +![Ubuntu 安装完成][42] + +如果一切按计划进行，你应该会在计算机重新启动时看到类似的屏幕，选择 Ubuntu 或 Windows 10，其他选项是用于故障排除，所以我们一般不会选择进入其中。 + +![选择操作系统][43] + +尝试启动并进入 Ubuntu 或 Windows 以测试是否安装成功并确保一切按预期地正常工作。如果没有问题，你已经在你的电脑上安装了 Windows 和 Ubuntu 。 + +-------------------------------------------------------------------------------- + +via: https://opensource.com/article/18/5/dual-boot-linux + +作者：[Jay LaCroix][a] +选题：[lujun9972](https://github.com/lujun9972) +译者：[Auk7F7](https://github.com/Auk7F7) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]:https://opensource.com/users/jlacroix +[1]:https://www.microsoft.com/en-us/software-download/windows10 +[2]:https://www.ubuntu.com/download/desktop +[3]:http://www.etcher.io +[4]:/file/397066 +[5]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_01.png "Windows setup" +[6]:/file/397076 +[7]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_03.png "Enter product key" +[8]:data:image/gif;base64,R0lGODlhAQABAPABAP///wAAACH5BAEKAAAALAAAAAABAAEAAAICRAEAOw== "Click and drag to move" +[9]:/file/397081 +[10]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_04.png "Select Windows version" +[11]:/file/397086 +[12]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_05.png "Accept license terms" +[13]:/file/397091 +[14]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_06.png "Select type of Windows installation" +[15]:/file/397096 +[16]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_07.png "Hard drive configuration" +[17]:/file/397101 +[18]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_08.png "Create a new partition" +[19]:/file/397106 +[20]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_09.png "Leaving a partition with unallocated space" +[21]:/file/397111 +[22]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_10.png "Installing Windows" +[23]:/file/397116 +[24]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_11.png "Windows desktop" +[25]:/file/397121 +[26]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_12.png "Ubuntu installation welcome screen" +[27]:/file/397126 +[28]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_13.png "Ubuntu desktop" +[29]:/file/397131 +[30]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_15.png "Select language in Ubuntu" +[31]:/file/397136 +[32]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_16.png "Select keyboard in Ubuntu" +[33]:/file/397141 +[34]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_17.png "Choose Ubuntu installation options" +[35]:/file/397146 +[36]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_18.png "Install Ubuntu alongside Windows" +[37]:/file/397151 +[38]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_18b.png "Allocate drive space" +[39]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_19.png "Confirmation screen" +[40]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_20.png "Select location" +[41]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_21.png "Account setup" +[42]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_22.png "Installation complete" +[43]:https://opensource.com/sites/default/files/uploads/linux-dual-boot_23.png "Chose which OS to use" diff --git a/translated/tech/20180707 Version Control Before Git with CVS.md b/translated/tech/20180707 Version Control Before Git with CVS.md new file mode 100644 index 0000000000..6532d65e7c --- /dev/null +++ b/translated/tech/20180707 Version Control Before Git with CVS.md @@ -0,0 +1,316 @@ +Git 之前使用 CVS 进行版本控制 +====== +Github 网站于 2008 年发布。如果你的软件工程师职业生涯跟我一样，也是晚于此时间的话，Git 可能是你用过的唯一版本控制软件。虽然其陡峭的学习曲线和不直观地用户界面时常会遭人抱怨，但不可否认的是， Git 已经成为人们学习版本控制的最佳选择。 2015 年，Stack Overflow 进行的开发者调查显示，69.3% 的被调查者在使用 Git，几乎是排名第二的 Subversion 版本控制系统使用者数量的两倍。2015 年之后，也许是因为 Git 太受欢迎了，大家对此话题不再感兴趣，所以 Stack Overflow 停止了关于开发人员使用版本控制系统软件的问卷调查。 + +Github 的发布时间距离 Git 自身发布时间很近。2005 年, Linus Torvalds 发布了 Git 的首个版本。现在的年经一代开发者可能很难想象“版本控制软件”生命周期所代表的世界并不仅仅只有 Git，虽然这样的世界诞生的时间并不长。除了 Git 外，还有很多可供选择。开源开发者较喜欢 Subversion，企业和视频游戏公司使用 Perforce （到如今有些仍在用），而 Linux 内核项目依赖于名为 BitKeeper 的版本控制系统。 + +其中一些系统，特别是 BitKeeper，会让年经一代的 Git 用户感觉很熟悉，上手也很快，但大多数相差很大。除了 BitKeeper，Git 之前的版本控制系统都是以不同的架构模型为基础运行的。作者 Eric Sink 在他的 [Version Control By Example][8] 一书中对版本控制进行了分类，按其说法，Git 属于第三代版本控制系统，而大多数 Git 的前身，即流行于二十世纪九零年代和二十一世纪早期的系统，都属于第二代版本控制系统。第三代版本控制系统是分布式的，第二代是集中式。你们以前大概都听过 Git 被描述为一款“分布式”版本控制系统。我一直都不明白分布式/集中式之间的区别，随后自己亲自安装了一款第二代的集中式版本控件系统，并做了相关实验，至少明白了一些。 + +我安装的版本系统是 CVS。CVS，即 `Concurrent Versions System` 的缩写，是最初的第二代版本控制系统。大约十年，它是最为流行的版本控制系统，直到 2000 年被 Subversion 所取代。即便如此，Subversion 被认为是 “CVS 但做的更好”，这更进一步突出了 CVS 在二十世纪九零年代的主导地位。 + +CVS 最早是由一位名叫 Dick Grune 的荷兰科学家在 1986 年间开发的，当时有一个编译器项目，他正在寻找一种能与其学生合作的方法。CVS 最初仅仅只是一个包装了 RCS（修订控制系统) 的 Shell 脚本集合，Grune 想改进这个第一代的版本控制系统。 RCS 是按悲观锁模式工作的，这意味着两个程序员不可以同时处理同一个文件。需要编辑一个文件话，首先得向 RCS 系统请求一个排它锁，锁定此文件直到完成编辑，如果你想编辑的文件有人正在编辑，你就必须等待。CVS 在 RCS 基础上改进，并把悲观锁模型替换成乐观锁模型，迎来了第二代版本控制系统的时代。现在，程序员可以同时编辑同一个文件、合并编辑部分，随后解决合并冲突问题。（后来接管 CVS 项目的工程师布莱恩·柏林(Brian Berliner)于 1990 年撰写了一篇关于 CVS 创新的非常易读的 [论文][1]。） + +从这个意义上来讲，CVS 与 Git 并无差异，因为 Git 也是运行于乐观锁模式的，但也仅仅只有此点相似。实际上，Linus Torvalds 开发 Git 时，他的一个指导原则是 WWCVSND，即 “What Would CVS +Not Do (CVS 不能做的).” 每当他做决策时，他都会力争选择那些在 CVS 设计里没有使用的功能选项。所以即使 CVS 要早于 Git 十多年，但它对 Git 的影响是为负数的。 + +我非常喜欢折腾 CVS。我认为要弄明白为什么 Git 的分布式特性是对以前的版本控制系统的较大改善的话，除了折腾 CVS 外，没有更好的办法。因此，我邀请您跟我一起来一段激动人心的旅程，并在接下来的十分钟内了解下这个近十年来无人使用的软件。（可以看看修正部分） + +### CVS 入门 + +CVS 的安装教程可以在其 [项目主页][2] 上找到。MacOS 系统的话，可以使用 Homebrew 安装。 + +由于 CVS 是集中式的，所以它有客户端和服务端之区分，这种模式 Git 是没有的。两端分别有不同的可执行文件，其区别不太明显。但要开始使用 CVS 的话，即使只在您的本地机器上使用，也必须设置 CVS 的服务后端。 + +CVS 的后端，即所有代码的中央存储区，被叫做存储库 (repository)。在 Git 中每一个项目都有一个存储库，而 CVS 中一个存储库就包含所有的项目。尽管有办法保证一次只能访问一个项目，但一个中央存储库包含所有东西是改变不了的。 + +要在本地创建存储库的话，请运行 `init` 命令。您可以像如下所示在家(home)目录创建，也可以在您本地的任何地方创建。 + +``` +$ cvs -d ~/sandbox init +``` + +CVS 允许您将选项传递给 `cvs` 命令本身或 `init` 子命令。出现在 `cvs` 命令之后的选项默认是全局的，而出现在子命令之后的是子命令特有选项。上面所示例子中，`-d` 标志是全局选项。在这儿是告诉 CVS 我们想要创建存储库路径在哪里，但通用的 `-d` 标志指的是我们想要使用的且已经存在的存储库位置。一直使用 `-d` 标志很单调乏味，所以可以设置 `CVSROOT` 环境变量来代替。 + +因为我们只是在本地操作，所以仅仅使用 `-d` 参考来传送路径就可以，但也可以包含个主机名。 + +此命令在您的家目录创建了一个名叫 `sandbox` 的目录。 如果您列出 `sandbox` 内容，会发现下面包含有 `CVSROOT` 的目录。请不要把此目录与我们的环境变量混淆，它保存存储库的管理文件。 + +恭喜！ 您刚刚创建了第一个 CVS 存储库。 + +### 检入代码 + +假设你决定留存下自己喜欢的颜色清单。因为您是一个有艺术倾向但很健忘的人，所以你键入颜色列表清单，并保存到一个叫 `favorites.txt` 的文件中： + +``` +blue +orange +green + +definitely not yellow +``` + +我们也假设您把文件保存到一个叫 `colors` 的目录中。现在你想要把喜欢的颜色列表清单置于版本控制之下，因为从现在起的五十年间会回顾下，随着时间的推移自己的品味怎么变化，这件事很有意思。 + +为此，您必须将您的目录导入为新的 CVS 项目。可以使用 `import` 命令： + +``` +$ cvs -d ~/sandbox import -m "" colors colors initial +N colors/favorites.txt + +No conflicts created by this import +``` + +这里我们再次使用 `-d` 标志来指定存储库的位置，其余的参数是传输给 `import ` 子命令的。必须要提供一条消息，但这儿没必要，所以留空。下一个参数 `colors`，指定了存储库中新目录的名字，这儿给的名字跟检入的目录名称一致。最后的两个参数分别指定了 vendor 标签和 release 标签。我们稍后就会谈论标签。 + +我们刚将 `colors` 项目拉入 CVS 存储库。将代引入 CVS 有很多种不同的方法，但这是 [Pragmatic Version Control Using CVS][3] 一书所推荐方法，这是一本关于 CVS 的程序员实用指导书籍。使用这种方法有点尴尬的就是你得重新检出 (check out) 工作项目，即使已经存在有 `colors` 此项目了。不要使用该目录，首先删除它，然后从 CVS 中检出刚才的版本，如下示： + +``` +$ cvs -d ~/sandbox co colors +cvs checkout: Updating colors +U colors/favorites.txt +``` + +这个过程会创建一个新的目录，也叫做 `colors`。此目录里会发现您的源文件 `favorites.txt`，还有一个叫 `CVS` 的目录。这个 `CVS` 目录基本上与 Git 存储库的 `.git` 目录等同。 + +### 做出改动 + +准备旅行。 + +和 Git 一样，CVS 也有 `status` 命令： + +``` +$ cvs status +cvs status: Examining . +=================================================================== +File: favorites.txt Status: Up-to-date + + Working revision: 1.1.1.1 2018-07-06 19:27:54 -0400 + Repository revision: 1.1.1.1 /Users/sinclairtarget/sandbox/colors/favorites.txt,v + Commit Identifier: fD7GYxt035GNg8JA + Sticky Tag: (none) + Sticky Date: (none) + Sticky Options: (none) +``` + +到这儿事情开始陌生起来了。CVS 没有提交对象这一概念。如上示，有一个叫 “提交标识符 Commit Identifier ” 的东西，但这可能是一个较新版本的标识，在 2003 年出版的《Pragmatic Version Control Using CVS》一书中并没有提到 “提交标识符” 这个概念。 （CVS 的最新版本于 2008 年发布的。） + +在 Git 中，我们所谈论某文件版本其实是在谈论如 `commit 45de392` 相关的东西，而 CVS 中文件是独立版本化的。文件的第一个版本为 1.1 版本，下一个是 1.2 版本，依此类推。涉及分支时，会在后面添加扩展数字。因此您会看到如上所示的 `1.1.1.1` 的内容，这就是示例的版本号，即使我们没有创建分支，似乎默认的会给加上。 + +一个项目中会有很多的文件和很多次的提交，如果您运行 `cvs log` 命令（等同于 `git log`），会看到每个文件提交历史信息。同一个项目中，有可能一个文件处于 1.2 版本，一个文件处于 1.14 版本。 + +继续，我们对 1.1 版本的 `favorites.txt` 文件做些修改： + +``` + blue + orange + green ++cyan + + definitely not yellow +``` + +修改完成，就可以运行 `cvs diff` 来看看 CVS 发生了什么： + +``` +$ cvs diff +cvs diff: Diffing . +Index: favorites.txt +=================================================================== +RCS file: /Users/sinclairtarget/sandbox/colors/favorites.txt,v +retrieving revision 1.1.1.1 +diff -r1.1.1.1 favorites.txt +3a4 +> cyan +``` + +CVS 识别出我们我在文件中添加了一个包含颜色 "cyan" 的新行。（实际上，它说我们已经对 “RCS” 文件进行了更改；你可以看到，CVS 底层使用的还是 RCS。） 此差异指的是当前工作目录中的 `favorites.txt` 副本与存储库中 1.1.1.1 版本的文件之间的差异。 + +为了更新存储库中的版本，我们必须提交更改。Git 中，这个操作要好几个步骤。首先，暂存此修改，使其在索引中出现，然后提交此修改，最后，为了使此修改让其他人可见，我们必须把此提交推送到源存储库中。 + +而 CVS 中，只需要运行 `cvs commit` 命令就搞定一切。CVS 会查找所有修改的东西，进行捆绑，然后把它们放到存储库中。 + +``` +$ cvs commit -m "Add cyan to favorites." +cvs commit: Examining . +/Users/sinclairtarget/sandbox/colors/favorites.txt,v <-- favorites.txt +new revision: 1.2; previous revision: 1.1 +``` + +我已经习惯了 Git, 所以这种操作会让我感到十分恐惧。因为没有变更暂存区的机制，工作目录下修改的一些老旧的东西都会一股脑给提交到公共存储库中。您有过因为不爽，私下里重写了某个同事不佳的功能实现，但仅仅只是自我宣泄一下并不想让他知道的时候吗？如果不小心提交上去了，就太糟糕了，他会认为你是个混蛋。在推送之前，你也不能修改提交过的东西了，因为提交就是推送。还是您愿意花费 40 分钟的时间来反复运行 `git rebase -i` 命令，以使得本地提交历史记录跟数学证明一样清晰严谨？很遗憾，CVS 里不支持，结果就是，大家都会看到您没有先写测试用例。 + +不过，到现在我终于理解了为什么那么多人都觉得 Git 没必要搞那么复杂。对那些早已经习惯直接 `cvs commit` 的人来说，进行暂存变更和推送变更操作确实是毫无意义的差事。 + +人们常谈论 Git 是一个 “分布式” 系统，其意思中分布式与非分布式的主要区别为：在 CVS 中，无法进行本地提交。一次提交操作就是向中央存储库提交代码，所以没有网络连接，刚无法执行此操作，获取到本地的只是您的工作目录；在 Git 中，会有一个完完全全的本地存储库，所以即使断网了也可以无间断执行提交操作。您还可以进行编辑提交内容、回退、分支和随心所欲的操作，且无人知晓。 + +虽然提交是个很大的话题，但 CVS 用户很少会关注。提交会包含很多的内容修改及今天我们盼望看到的十多次提交请求。还有很特别的，提交触发 CI 构建和触发自动测试程序等。 + +现在我们运行 `cvs status`，会看到产生了文件的新版本： + +``` +$ cvs status +cvs status: Examining . +=================================================================== +File: favorites.txt Status: Up-to-date + + Working revision: 1.2 2018-07-06 21:18:59 -0400 + Repository revision: 1.2 /Users/sinclairtarget/sandbox/colors/favorites.txt,v + Commit Identifier: pQx5ooyNk90wW8JA + Sticky Tag: (none) + Sticky Date: (none) + Sticky Options: (none) +``` + +### 合并 + +如上所述，在 CVS 中，你可以同时编辑其他人正在编辑的文件。这是 CVS 对 RCS 的重大改进。当需要将更改的部分重新组合在一起时会发生什么？ + +假设您邀请了一些来将他们喜欢的颜色添加到您的列表中。在他们添加的时候，您确定了不再喜欢绿色，然后把它从列表中删除。 + +当你提交更新的时候，会发现 CVS 报出了个问题： + +``` +$ cvs commit -m "Remove green" +cvs commit: Examining . +cvs commit: Up-to-date check failed for `favorites.txt' +cvs [commit aborted]: correct above errors first! +``` + +好像是朋友们首先提交了更新。所以您的 `favorites.txt` 文件版本没有更新到存储库中的最新版本。此时运行 `cvs status` 就可以看到，本地的 `favorites.txt` 文件副本有一些变更且是 1.2 版本的而存储库上的版本号是 1.3，如下示： + +``` +$ cvs status +cvs status: Examining . +=================================================================== +File: favorites.txt Status: Needs Merge + + Working revision: 1.2 2018-07-07 10:42:43 -0400 + Repository revision: 1.3 /Users/sinclairtarget/sandbox/colors/favorites.txt,v + Commit Identifier: 2oZ6n0G13bDaldJA + Sticky Tag: (none) + Sticky Date: (none) + Sticky Options: (none) +``` + +你可以运行 `cvs diff` 来了解 1.2 版本与 1.3 版本的确切差异： + +``` +$ cvs diff -r HEAD favorites.txt +Index: favorites.txt +=================================================================== +RCS file: /Users/sinclairtarget/sandbox/colors/favorites.txt,v +retrieving revision 1.3 +diff -r1.3 favorites.txt +3d2 +< green +7,10d5 +< +< pink +< hot pink +< bubblegum pink +``` + +看来我们的朋友是真的喜欢粉红色，但好在他们编辑的是此文件的不同部分，所以很容易地合并此修改。跟 `git pull` 类似，只要运行 `cvs update` 命令，CVS 就可以为我们做合并操作，如下示： + +``` +$ cvs update +cvs update: Updating . +RCS file: /Users/sinclairtarget/sandbox/colors/favorites.txt,v +retrieving revision 1.2 +retrieving revision 1.3 +Merging differences between 1.2 and 1.3 into favorites.txt +M favorites.txt +``` + +此时查看 `favorites.txt` 文件内容的话，你会发现你的朋友对文件所做的更改已经包含进去了，你的修改也在里面。现在你可以自由的提交文件了，如下示： + +``` +$ cvs commit +cvs commit: Examining . +/Users/sinclairtarget/sandbox/colors/favorites.txt,v <-- favorites.txt +new revision: 1.4; previous revision: 1.3 +``` + +最终的结果就跟在 Git 中运行 `git pull --rebase` 一样。你的修改是添加在你朋友的修改之后的，所以没有 “合并提交” 这操作。 + +某些时候，对同一文件的修改可能导致冲突。例如，如果你的朋友把 “green” 修改成 “olive”，同时你完全删除 “green”，就会出现冲突。早期的时候，正是这种情况导致人们担心 CVS 不安全，而 RCS 的悲观锁机制可以确保此情况永不会发生。但 CVS 提供了一个安全保障机制，可以确保不会自动的覆盖任何人的修改。因此，当运行 `cvs update` 的时候，你必须告诉 CVS 想要做哪些修改才能继续下一步操作。CVS 会标记文件的所有变更，这跟 Git 检测到合并冲突时所做的方式一样，然后，你必须手工编辑文件，选择需要保留的变更进行合并。 + +这儿需要注意的有趣事情就是在进行提交之前必须修复并合并冲突。这是 CVS 集中式特性的另一个结果。而在 Git 里，在推送本地的提交内容之前，您都不用担心合并冲突问题。 + +由于 CVS 没有易于记录的提交对象，因此对变更集合进行分组的唯一方法就是对于特定的工作目录状态打个标记。 + +创建一个标记是很容易的： + +``` +$ cvs tag VERSION_1_0 +cvs tag: Tagging . +T favorites.txt +``` + +稍后，运行 `cvs update` 命令并把标签传输给 `-r` 标志就可以把文件恢复到此状态，如下示： + +``` +$ cvs update -r VERSION_1_0 +cvs update: Updating . +U favorites.txt +``` + +因为你需要一个标记来回退到早期的工作目录状态，所以 CVS 鼓励创建大量的抢占标记。例如，在重大的重构之前，你可以创建一个 `BEFORE_REFACTOR_01` 标记，如果重构出错，就可以使用此标记回退。你果想在项目范围上生成有差异的版本的话，也可以使用标记。基本上，我们使用 CVS 来管理的, 对于今天日常所做的所有事情都是预测性和计划性的，所以需要打上标记，以备回退修改。 + +可以在 CVS 中创建分支。分支只是一种特殊的标记，如下示： + +``` +$ cvs rtag -b TRY_EXPERIMENTAL_THING colors +cvs rtag: Tagging colors +``` + +（顺便提醒一下读者）这命令仅仅只是创建了分支，所以还需要使用 `cvs update` 命令来切换分支，如下示： + +``` +$ cvs update -r TRY_EXPERIMENTAL_THING +``` + +上面的命令就会把您的当前工作目录切换到新的分支，但《Pragmatic Version Control Using CVS》一书实际上是建议创建一个新的目录来间接替代新分支。估计，其作者发现在 CVS 里切换目录要比切换分支来得更简单吧。 + +此书也建议不要从现有分支创建分支，而只在主线分支，Git 中被叫做 `master`，上创建分支。一般来说，分支在 CVS 中主认为是 “高级” 技能。而在 Git 中，您几乎可以无理由的就创建新分支，但 CVS 中要在真正需要的时候才能创建，比如发布项目。 + +稍后可以使用 `cvs update` 和 `-j` 标志将分支合并回主线： + +``` +$ cvs update -j TRY_EXPERIMENTAL_THING +``` + +### 感谢历史上的贡献者 + +2007 年，Linus Torvalds 在 Google 进行了一场关于 Git 的 [演讲][4]（译者注：需要梯子，国内用户可以访问 [腾讯视频][9]）。当时 Git 是很新的东西，整场演讲基本上都是在说服满屋子都持有怀疑态度的程序员们，尽管 Git 是如此的与众不同，也应该使用 Git。如果没有看过这个视频的话，我强烈建议你去看看。Linus 是个有趣的演讲者，即使他有些傲慢。他非常出色地解释了为什么分布式的版本控制系统要比集中式的优秀。他的很多评论是直接针对 CVS 的。 + +Git 是一个 [相当复杂的工具][5]。学习起来是一个令人沮丧的经历，但也不断的给我惊喜，Git 还能做这样的事情。相比之下，CVS 简单明了，但是，许多我们认为理所当然的操作都做不了。想要对 Git 的强大功能和灵活性有全新的认识的话，就回过头来用用 CVS 吧，这是种很好的学习方式。这很好的诠释了为什么理解软件的开发历史可以让人受益匪浅。重拾过期淘汰的工具可以让我们理解今天所使用的工具后面所隐藏的哲理。 + +如果您喜欢此博文的话，每两周会有一次更新！请在 Twitter 上关注 [@TwoBitHistory][6] 或都通过 [RSS feed][7] 订阅，新博文出来会有通知。 + +#### 修正 + +有人告诉我，有很多组织企业，特别是像做医疗设备软件等这种规避风险类的企业，仍在使用 CVS。这些企业中的程序员通过使用一些小技巧来解决 CVS 的限制，例如为几乎每个更改创建一个新分支以避免直接提交给 `HEAD`。 （感谢 Michael Kohne 指出这一点。） + + +-------------------------------------------------------------------------------- + +via: https://twobithistory.org/2018/07/07/cvs.html + +作者：[Two-Bit History][a] +选题：[lujun9972][b] +译者：[runningwater](https://github.com/runningwater) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]: https://twobithistory.org +[b]: https://github.com/lujun9972 +[1]: https://docs.freebsd.org/44doc/psd/28.cvs/paper.pdf +[2]: https://www.nongnu.org/cvs/ +[3]: http://shop.oreilly.com/product/9780974514000.do +[4]: https://www.youtube.com/watch?v=4XpnKHJAok8 +[5]: https://xkcd.com/1597/ +[6]: https://twitter.com/TwoBitHistory +[7]: https://twobithistory.org/feed.xml +[8]: https://ericsink.com/vcbe/index.html +[9]: https://v.qq.com/x/page/o0772kqh5iv.html diff --git a/translated/tech/20180709 5 Firefox extensions to protect your privacy.md b/translated/tech/20180709 5 Firefox extensions to protect your privacy.md new file mode 100644 index 0000000000..972228d9e5 --- /dev/null +++ b/translated/tech/20180709 5 Firefox extensions to protect your privacy.md @@ -0,0 +1,63 @@ +[#]: collector: (lujun9972) +[#]: translator: (geekpi) +[#]: reviewer: ( ) +[#]: publisher: ( ) +[#]: subject: (5 Firefox extensions to protect your privacy) +[#]: via: (https://opensource.com/article/18/7/firefox-extensions-protect-privacy) +[#]: author: ([Chris Short](https://opensource.com/users/chrisshort) +[#]: url: ( ) + +5 个保护你隐私的 Firefox 扩展 +====== + + + +在剑桥分析公司这件事后，我仔细研究了我让 Facebook 渗透到我的网络生活的程度。由于我一般担心单点故障，我不是一个使用社交登录的人。我使用密码管理器为每个站点创建唯一的登录（你也应该这样做）。 + +我最担心的 Facebook 对我的数字生活的普遍侵扰。在深入了解剑桥分析公司这件事后，我几乎立即卸载了 Facebook 的移动程序。我还从 Facebook [取消连接了所有应用、游戏和网站][1]。是的，这将改变你在 Facebook 上的体验，但它也将保护您的隐私。作为一名有遍布全球朋友的人，保持 Facebook 的社交连接对我来说非常重要。 + +我还仔细审查了其他服务。我检查了 Google、Twitter、GitHub 以及任何未使用的连接应用。但我知道这还不够。我需要我的浏览器主动防止侵犯我隐私的行为。我开始研究如何做到最好。当然，我可以锁定浏览器，但是我需要使我用的网站和工具正常使用，同时试图防止它们泄露数据。 + +以下是五种可在使用浏览器时保护你隐私的工具。前三个扩展可用于 Firefox 和 Chrome，而后两个仅适用于 Firefox。 + +### Privacy Badger + +我已经使用 [Privacy Badger][2] 有一段时间了。其他内容或广告拦截器做得更好吗？也许。很多内容拦截器的问题在于它们“付费显示”。这意味着他们有收费的“合作伙伴”白名单。这就站在了为什么存在内容拦截器的对立面。Privacy Badger 是由电子前沿基金会 （EFF） 制作的，这是一家以捐赠为基础的商业模式的非营利实体。Privacy Badger 承诺从你的浏览习惯中学习，并且很少需要调整。例如，我只需将一些网站列入白名单。Privacy Badger 允许精确控制在哪些站点上启用哪些跟踪器。这是我的第一个无论在哪个浏览器必须安装的扩展。 + +### DuckDuckGo Privacy Essentials + +搜索引擎 DuckDuckGo 通常有隐私意识。[DuckDuckGo Privacy Essentials][3] 适用于主流的移动设备和浏览器。它的独特之处在于它根据你提供的设置对网站进行评分。例如，即使启用了隐私保护，Facebook 也会获得 D。同时，[chrisshort.net][4] 在启用隐私保护时获得 B 和禁用时获得 C。如果你因任何原因不喜欢于 EFF 或 Privacy Badger，我会推荐 DuckDuckGo Privacy Essentials（选择一个，而不是两个，因为它们基本上做同样的事情）。 + +### HTTPS Everywhere + +[HTTPS Everywhere][5] 是 EFF 的另一个扩展。根据 HTTPS Everywhere 的说法，“网络上的许多网站都通过 HTTPS 提供一些有限的加密支持，但使它难以使用。例如，它们可能默认为未加密的 HTTP 或在加密的页面里面使用返回到未加密站点的链接。HTTPS Everywhere 扩展通过使用聪明的技术将对这些站点的请求重写为 HTTPS 来解决这些问题。“虽然许多网站和浏览器在实施 HTTPS 方面越来越好，但仍有很多网站仍需要帮助。HTTPS Everywhere 将尽力确保你的流量已加密。 + +### NoScript Security Suite + +[NoScript Security Suite][6] 不适合胆小的人。虽然这个 Firefox 独有扩展“允许 JavaScript、Java、Flash 和其他插件只能由你选择的受信任网站执行”，但它并不能很好地确定你的选择。但是，毫无疑问，防止泄漏数据的可靠方法是不执行可能会泄露数据的代码。NoScript 通过其“基于白名单的抢占式脚本阻止”实现了这一点。这意味着你需要为尚未加入白名单的网站构建白名单。请注意，NoScript 仅适用于 Firefox。 + +### Facebook Container + +Facebook Container][7] 使 Firefox 成为我在使用 Facebook 时的唯一浏览器。 “Facebook Container 的工作原理是将你的 Facebook 身份隔离到一个单独的容器中，这使得 Facebook 更难以使用第三方 Cookie 跟踪你访问其他网站。” 这意味着 Facebook 无法窥探浏览器中其他地方发生的活动。 突然间，这些令人毛骨悚然的广告将停止频繁出现（假设你在移动设备上卸载了 Facebook 应用）。 在隔离的空间中使用 Facebook 将阻止任何额外的数据收集。 请记住，你已经提供了 Facebook 数据，而 Facebook Container 无法阻止这些数据被共享。 + +这些是我浏览器隐私的首选扩展。 你的是什么？ 请在评论中分享。 + +-------------------------------------------------------------------------------- + +via: https://opensource.com/article/18/7/firefox-extensions-protect-privacy + +作者：[Chris Short][a] +选题：[lujun9972](https://github.com/lujun9972) +译者：[geekpi](https://github.com/geekpi) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]:https://opensource.com/users/chrisshort +[1]:https://www.facebook.com/help/211829542181913 +[2]:https://www.eff.org/privacybadger +[3]:https://duckduckgo.com/app +[4]:https://chrisshort.net +[5]:https://www.eff.org/https-everywhere +[6]:https://noscript.net/ +[7]:https://addons.mozilla.org/en-US/firefox/addon/facebook-container/ \ No newline at end of file diff --git a/translated/tech/20180807 5 reasons the i3 window manager makes Linux better.md b/translated/tech/20180807 5 reasons the i3 window manager makes Linux better.md deleted file mode 100644 index 428665c170..0000000000 --- a/translated/tech/20180807 5 reasons the i3 window manager makes Linux better.md +++ /dev/null @@ -1,109 +0,0 @@ -i3窗口管理器让Linux更好的五个原因 -====== - - - -Linux（和一般的开源软件） 最美好的一点是在不同的替代方案中进行选择的自由，以满足我们的需求。 - -我使用 Linux 已经很长时间了，但我从来没有对可用的桌面环境完全满意。直到去年 [Xfce][1] 是我认为在功能和性能之间的一个接近优秀的妥协。然后我发现 [i3][2] 一个惊人的软件改变了我的生活 - -I3 是一个平铺窗口管理器。窗口管理器的目标是控制窗口系统中窗口的外观和位置。窗口管理器通常用作功能齐全的桌面环境 (如 GONME 或 Xfce ) 的一部分, 但也有一些可以用作独立的应用程序。 - -平铺式窗口管理器会自动排列窗口, 以不重叠的方式占据整个屏幕。其他流行的平铺式窗口管理器包括 [wmii][3] 和 [xmonad][4] 。 - -![i3 tiled window manager screenshot][6] - -带有三个的 i3 屏幕截图 - -以下是我使用 i3 窗口管理器的五个首要原因，并推荐它以获得更好的 Linux 桌面体验。 - -### 1\.简化的艺术 - -I3 速度很快。它既不冗杂, 也不花哨。它的设计简单而高效。作为开发人员, 我重视这些功能， 因为我可以使用额外的功能为我最喜欢的开发工具助力， 或者使用容器或虚拟机在本地测试内容。 - -此外， I3 是一个窗口管理器，与功能齐全的桌面环境不同，它并不规定您应该使用的应用程序。您是否想使用 Xfce 的 Thunar 作为文件管理器？GNOME 的 gedit 去编辑文本? I3 并不在乎。选择对您的工作流最有意义的工具，I3 将以相同的方式管理它们。 - -### 2\. 屏幕实际使用面积 - -作为平铺式窗口管理器, I3 将自动 "平铺" 或以不重叠的方式定位窗口, 类似于在墙上放置瓷砖。因为您不需要担心窗口定位, i3 一般会更好地利用您的屏幕空间。它还可以让您更快地找到您需要的东西。 - -对于这种情况有很多有用的例子。例如, 系统管理员可以打开多个？来同时监视或在不同的远程系统上工作;开发人员可以使用他们最喜欢的 IDE 或编辑器和几个？来测试他们的程序。 - -此外, i3 具有灵活性。如果您需要为特定窗口提供更多空间, 请启用全屏模式或切换到其他布局, 如堆叠或选项卡式（标签式）。 - -### 3\. 键盘驱动的工作流程 - -i3 广泛使用键盘快捷键来控制环境的不同方面。其中包括打开？和其他程序、调整大小和定位窗口、更改布局, 甚至退出 i3。当您开始使用 i3 时, 您需要记住其中的一些快捷方式来绕行，随着时间的推移，您会使用更多的快捷方式。 - -主要好处是, 您不需要经常用键盘和鼠标切换上下文。通过练习, 意味着您将提高工作流程的速度和效率。 - -例如， 要打开新的？，请按 ` + ` .由于窗口是自动定位的, 您可以立即开始键入命令。结合一个很好的？驱动的文本编辑器 (如 Vim) 和一个以键盘为焦点的浏览器，形成一个完全由键盘驱动的工作流程。 - -在 i3 中, 您可以为所有内容定义快捷方式。下面是一些示例: - - * 打开？ - * 打开浏览器 - * 更改布局 - * 调整窗口大小 - * 控制音乐播放器 - * 切换工作区 - -现在我已经习惯了这个工作形式，我已无法回到了常规的桌面环境。 - -### 4\. 灵活 - -i3 力求最小化，很少使用系统资源， 但这并不意味着它不可能漂亮。i3 具有灵活性, 可通过多种方式进行自定义， 以改善视觉体验。因为 i3 是一个窗口管理器, 所以它不提供启用自定义的工具，而是提供启用自定义的工具。您需要外部工具来实现这一点。一些例子: - - * 用 `feh` 定义桌面的背景图片。 - * 使用复合器管理器, 如`compton`以启用窗口淡入淡出和透明度等效果。 - * 用 `dmenu` 或 `rofi`以启用可从键盘快捷方式启动的可自定义菜单。 - * 用 `dunst` 用于桌面通知。 - - - -i3 是完全可配置的，您可以通过更新默认配置文件来控制它的各个方面。从更改所有键盘快捷键，到重新定义工作区的名称，再到修改状态栏，您都可以使 i3 以任何最适合您需要的方式运行。 - -![i3 with rofi menu and dunst desktop notifications][8] - -i3 与 `rofi` 菜单和 `dunst` 桌面通知。 - -最后, 对于更高级的用户， i3 提供了完整的进程间通信([IPC][9]) 界面， 允许您使用您最喜爱的语言来开发脚本或程序，以实现更多的自定义选项。 - -### 5\. 工作空间 - -在 i3 中, 工作区是对窗口进行分组的一种简单方法。您可以根据您的工作流以不同的方式对它们进行分组。例如, 您可以将浏览器放在一个工作区上, ？命令行放在另一个工作区上, 将电子邮件客户端放在第三个工作区上, 等等。您甚至可以更改 i3 的配置, 以便始终将特定应用程序分配给它们自己的工作区。 - -切换工作区既快速又简单。像 i3 中的往常一样，使用键盘快捷方式执行此操作。按 ` +num` 切换到工作区 `num` 。如果您养成了始终将应用程序组的窗口分配到同一工作区的习惯，则可以在它们之间快速切换，这使得工作区成为非常有用的功能。 - -此外，还可以使用工作区来控制多监视器的设置，其中每个监视器都可以获得初始工作区。如果切换到该工作区, 则切换到该监视器，而无需让手离开键盘。 - -最后，i3 中还有另一种特殊类型的工作空间: the scratchpad（便笺簿）。它是一个不可见的工作区，通过按快捷方式显示在其他工作区的中间。这是一种方便的方式来访问您经常使用的窗口或程序，如电子邮件客户端或音乐播放器。 - -### 尝试一下吧 - -如果您重视简单性和效率， 并且不抵触使用键盘, i3 就是您的窗口管理器。有人说是为高级用户准备的，但情况不一定如此。你需要学习一些基本的快捷方式来度过开始的阶段，不久就会越来越自然并且不假思索地使用它们。 - -这篇文章只是触及了 i3 表面能做的事情。欲了解更多详情, 请咨询 [i3's documentation][10]. - --------------------------------------------------------------------------------- - -via: https://opensource.com/article/18/8/i3-tiling-window-manager - -作者：[Ricardo Gerardi][a] -选题：[lujun9972](https://github.com/lujun9972) -译者：[lixinyuxx](https://github.com/lixinyuxx) -校对：[校对者ID](https://github.com/校对者ID) - -本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 - -[a]:https://opensource.com/users/rgerardi -[1]:https://xfce.org/ -[2]:https://i3wm.org/ -[3]:https://code.google.com/archive/p/wmii/ -[4]:https://xmonad.org/ -[5]:/file/406476 -[6]:https://opensource.com/sites/default/files/uploads/i3_screenshot.png "i3 tiled window manager screenshot" -[7]:/file/405161 -[8]:https://opensource.com/sites/default/files/uploads/rofi_dunst.png "i3 with rofi menu and dunst desktop notifications" -[9]:https://i3wm.org/docs/ipc.html -[10]:https://i3wm.org/docs/userguide.html diff --git a/translated/tech/20180907 6.828 lab tools guide.md b/translated/tech/20180907 6.828 lab tools guide.md deleted file mode 100644 index 1396289ad1..0000000000 --- a/translated/tech/20180907 6.828 lab tools guide.md +++ /dev/null @@ -1,200 +0,0 @@ -6.828 实验工具指南 -====== -### 6.828 实验工具指南 - -熟悉你的环境对高效率的开发和调试来说是至关重要的。本文将为你简单概述一下 JOS 环境和非常有用的 GDB 和 QEMU 命令。话虽如此，但你仍然需要去阅读 GDB 和 QEMU 手册，来理解这些强大的工具如何使用。 - -#### 调试小贴士 - -##### 内核 - -GDB 是你的朋友。使用 `qemu-gdb target`(或它的变体 `qemu-gdb-nox`）使 QEMU 等待 GDB 去绑定。下面在调试内核时用到的一些命令，可以去查看 GDB 的资料。 - -如果你遭遇意外的中断、异常、或三重故障，你可以使用 `-d` 参数要求 QEMU 去产生一个详细的中断日志。 - -调试虚拟内存问题时，尝试 QEMU 监视命令 `info mem`（提供内存高级概述）或 `info pg`（提供更多细节内容）。注意，这些命令仅显示**当前**页表。 - -（在实验 4 以后）去调试多个 CPU 时，使用 GDB 的线程相关命令，比如 `thread` 和 `info threads`。 - -##### 用户环境（在实验 3 以后） - -GDB 也可以去调试用户环境，但是有些事情需要注意，因为 GDB 无法区分开多个用户环境或用户环境与内核环境。 - -你可以使用 `make run-name`（或编辑 `kern/init.c` 目录）来指定 JOS 启动的用户环境，为使 QEMU 等待 GDB 去绑定，使用 `run-name-gdb` 的变体。 - -你可以符号化调试用户代码，就像调试内核代码一样，但是你要告诉 GDB，哪个符号表用到符号文件命令上，因为它一次仅能够使用一个符号表。提供的 `.gdbinit` 用于加载内核符号表 `obj/kern/kernel`。对于一个用户环境，这个符号表在它的 ELF 二进制文件中，因此你可以使用 `symbol-file obj/user/name` 去加载它。不要从任何 `.o` 文件中加载符号，因为它们不会被链接器迁移进去（库是静态链接进 JOS 用户二进制文件中的，因此这些符号已经包含在每个用户二进制文件中了）。确保你得到了正确的用户二进制文件；在不同的二直制文件中，库函数被链接为不同的 EIP，而 GDB 并不知道更多的内容！ - -（在实验 4 以后）因为 GDB 绑定了整个虚拟机，所以它可以将时钟中断看作为一种控制转移。这使得从底层上不可能实现步进用户代码，因为一个时钟中断无形中保证了片刻之后虚拟机可以再次运行。因此可以使用 `stepi` 命令，因为它阻止了中断，但它仅可以步进一个汇编指令。断点一般来说可以正常工作，但要注意，因为你可能在不同的环境（完全不同的一个二进制文件）上遇到同一个 EIP。 - -#### 参考 - -##### JOS makefile - -JOS 的 GNUmakefile 包含了在各种方式中运行的 JOS 的许多假目标。所有这些目标都配置 QEMU 去监听 GDB 连接（`*-gdb` 目标也等待这个连接）。要在运行中的 QEMU 上启动它，只需要在你的实验目录中简单地运行 `gdb ` 即可。我们提供了一个 `.gdbinit` 文件，它可以在 QEMU 中自动指向到 GDB、加载内核符号文件、以及在 16 位和 32 位模式之间切换。退出 GDB 将关闭 QEMU。 - - * `make qemu` - 在一个新窗口中构建所有的东西并使用 VGA 控制台和你的终端中的串行控制台启动 QEMU。想退出时，既可以关闭 VGA 窗口，也可以在你的终端中按 `Ctrl-c` 或 `Ctrl-a x`。 - * `make qemu-nox` - 和 `make qemu` 一样，但仅使用串行控制台来运行。想退出时，按下 `Ctrl-a x`。这种方式在通过 SSH 拨号连接到 Athena 上时非常有用，因为 VGA 窗口会占用许多带宽。 - * `make qemu-gdb` - 和 `make qemu` 一样，但它与任意时间被动接受 GDB 不同，而是暂停第一个机器指令并等待一个 GDB 连接。 - * `make qemu-nox-gdb` - 它是 `qemu-nox` 和 `qemu-gdb` 目标的组合。 - * `make run-nam` - （在实验 3 以后）运行用户程序 _name_。例如，`make run-hello` 运行 `user/hello.c`。 - * `make run-name-nox`,`run-name-gdb`, `run-name-gdb-nox` - （在实验 3 以后）与 `qemu` 目标变量对应的 `run-name` 的变体。 - - - -makefile 也接受几个非常有用的变量： - - * `make V=1 …` -详细模式。输出正在运行的每个命令，包括参数。 - * `make V=1 grade` -在评级测试失败后停止，并将 QEMU 的输出放入 `jos.out` 文件中以备检查。 - * `make QEMUEXTRA=' _args_ ' …` -指定传递给 QEMU 的额外参数。 - - - -##### JOS obj/ - -在构建 JOS 时，makefile 也产生一些额外的输出文件，这些文件在调试时非常有用： - - * `obj/boot/boot.asm`、`obj/kern/kernel.asm`、`obj/user/hello.asm`、等等。 -引导加载器、内核、和用户程序的汇编代码列表。 - * `obj/kern/kernel.sym`、`obj/user/hello.sym`、等等。 -内核和用户程序的符号表。 - * `obj/boot/boot.out`、`obj/kern/kernel`、`obj/user/hello`、等等。 -内核和用户程序链接的 ELF 镜像。它们包含了 GDB 用到的符号信息。 - - - -##### GDB - -完整的 GDB 命令指南请查看 [GDB 手册][1]。下面是一些在 6.828 课程中非常有用的命令，它们中的一些在操作系统开发之外的领域几乎用不到。 - - * `Ctrl-c` -在当前指令处停止机器并打断进入到 GDB。如果 QEMU 有多个虚拟的 CPU，所有的 CPU 都会停止。 - * `c`（或 `continue`） -继续运行，直到下一个断点或 `Ctrl-c`。 - * `si`（或 `stepi`） -运行一个机器指令。 - * `b function` 或 `b file:line`（或 `breakpoint`） -在给定的函数或行上设置一个断点。 - * `b * addr`（或 `breakpoint`） -在 EIP 的 addr 处设置一个断点。 - * `set print pretty` -启用数组和结构的美化输出。 - * `info registers` -输出通用寄存器 `eip`、`eflags`、和段选择器。更多更全的机器寄存器状态转储，查看 QEMU 自己的 `info registers` 命令。 - * `x/ N x addr` -以十六进制显示虚拟地址 addr 处开始的 N 个词的转储。如果 N 省略，默认为 1。addr 可以是任何表达式。 - * `x/ N i addr` -显示从 addr 处开始的 N 个汇编指令。使用 `$eip` 作为 addr 将显示当前指令指针寄存器中的指令。 - * `symbol-file file` -（在实验 3 以后）切换到符号文件 file 上。当 GDB 绑定到 QEMU 后，它并不是虚拟机中进程边界内的一部分，因此我们要去告诉它去使用哪个符号。默认情况下，我们配置 GDB 去使用内核符号文件 `obj/kern/kernel`。如果机器正在运行用户代码，比如是 `hello.c`，你就需要使用 `symbol-file obj/user/hello` 去切换到 hello 的符号文件。 - - - -QEMU 将每个虚拟 CPU 表示为 GDB 中的一个线程，因此你可以使用 GDB 中所有的线程相关的命令去查看或维护 QEMU 的虚拟 CPU。 - - * `thread n` -GDB 在一个时刻只关注于一个线程（即：CPU）。这个命令将关注的线程切换到 n，n 是从 0 开始编号的。 - * `info threads` -列出所有的线程（即：CPU），包括它们的状态（活动还是停止）和它们在什么函数中。 - - - -##### QEMU - -QEMU 包含一个内置的监视器，它能够有效地检查和修改机器状态。想进入到监视器中，在运行 QEMU 的终端中按入 `Ctrl-a c` 即可。再次按下 `Ctrl-a c` 将切换回串行控制台。 - -监视器命令的完整参考资料，请查看 [QEMU 手册][2]。下面是 6.828 课程中用到的一些有用的命令： - - * `xp/ N x paddr` -显示从物理地址 paddr 处开始的 N 个词的十六进制转储。如果 N 省略，默认为 1。这是 GDB 的 `x` 命令模拟的物理内存。 - - * `info registers` -显示机器内部寄存器状态的一个完整转储。实践中，对于段选择器，这将包含机器的 _隐藏_ 段状态和局部、全局、和中断描述符表加任务状态寄存器。隐藏状态是在加载段选择器后，虚拟的 CPU 从 GDT/LDT 中读取的信息。下面是实验 1 中 JOS 内核处于运行中时的 CS 信息和每个字段的含义： -```c - CS =0008 10000000 ffffffff 10cf9a00 DPL=0 CS32 [-R-] -``` - - * `CS =0008` - -代码选择器可见部分。我们使用段 0x8。这也告诉我们参考全局描述符表（0x8 &4=0），并且我们的 CPL（当前权限级别）是 0x8&3=0。 - * `10000000` -这是段基址。线性地址 = 逻辑地址 + 0x10000000。 - * `ffffffff` -这是段限制。访问线性地址 0xffffffff 以上将返回段违规异常。 - * `10cf9a00` -段的原始标志，QEMU 将在接下来的几个字段中解码这些对我们有用的标志。 - * `DPL=0` -段的权限级别。一旦代码以权限 0 运行，它将就能够加载这个段。 - * `CS32` -这是一个 32 位代码段。对于数据段（不要与 DS 寄存器混淆了），另外的值还包括 `DS`，而对于本地描述符表是 `LDT`。 - * `[-R-]` -这个段是只读的。 - - * `info mem` -（在实验 2 以后）显示映射的虚拟内存和权限。比如： -``` - ef7c0000-ef800000 00040000 urw - efbf8000-efc00000 00008000 -rw - -``` - -这告诉我们从 0xef7c0000 到 0xef800000 的 0x00040000 字节的内存被映射为读取/写入/用户可访问，而映射在 0xefbf8000 到 0xefc00000 之间的内存权限是读取/写入，但是仅限于内核可访问。 - - * `info pg` -（在实验 2 以后）显示当前页表结构。它的输出类似于 `info mem`，但与页目录条目和页表条目是有区别的，并且为每个条目给了单独的权限。重复的 PTE 和整个页表被折叠为一个单行。例如： -``` - VPN range Entry Flags Physical page - [00000-003ff] PDE[000] -------UWP - [00200-00233] PTE[200-233] -------U-P 00380 0037e 0037d 0037c 0037b 0037a .. - [00800-00bff] PDE[002] ----A--UWP - [00800-00801] PTE[000-001] ----A--U-P 0034b 00349 - [00802-00802] PTE[002] -------U-P 00348 - -``` - -这里各自显示了两个页目录条目、虚拟地址范围 0x00000000 到 0x003fffff 以及 0x00800000 到 0x00bfffff。 所有的 PDE 都存在于内存中、可写入、并且用户可访问，而第二个 PDE 也是可访问的。这些页表中的第二个映射了三个页、虚拟地址范围 0x00800000 到 0x00802fff，其中前两个页是存在于内存中的、可写入、并且用户可访问的，而第三个仅存在于内存中，并且用户可访问。这些 PTE 的第一个条目映射在物理页 0x34b 处。 - - - - -QEMU 也有一些非常有用的命令行参数，使用 `QEMUEXTRA` 变量可以将参数传递给 JOS 的 makefile。 - - * `make QEMUEXTRA='-d int' ...` -记录所有的中断和一个完整的寄存器转储到 `qemu.log` 文件中。你可以忽略前两个日志条目、"SMM: enter" 和 "SMM: after RMS”，因为这些是在进入引导加载器之前生成的。在这之后的日志条目看起来像下面这样： -``` - 4: v=30 e=0000 i=1 cpl=3 IP=001b:00800e2e pc=00800e2e SP=0023:eebfdf28 EAX=00000005 - EAX=00000005 EBX=00001002 ECX=00200000 EDX=00000000 - ESI=00000805 EDI=00200000 EBP=eebfdf60 ESP=eebfdf28 - ... - -``` - -第一行描述了中断。`4:` 只是一个日志记录计数器。`v` 提供了十六进程的向量号。`e` 提供了错误代码。`i=1` 表示它是由一个 `int` 指令（相对一个硬件产生的中断而言）产生的。剩下的行的意思很明显。对于一个寄存器转储而言，接下来看到的就是寄存器信息。 - -注意：如果你运行的是一个 0.15 版本之前的 QEMU，日志将写入到 `/tmp` 目录，而不是当前目录下。 - - - --------------------------------------------------------------------------------- - -via: https://pdos.csail.mit.edu/6.828/2018/labguide.html - -作者：[csail.mit][a] -选题：[lujun9972][b] -译者：[qhwdw](https://github.com/qhwdw) -校对：[校对者ID](https://github.com/校对者ID) - -本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 - -[a]: https://pdos.csail.mit.edu -[b]: https://github.com/lujun9972 -[1]: http://sourceware.org/gdb/current/onlinedocs/gdb/ -[2]: http://wiki.qemu.org/download/qemu-doc.html#pcsys_005fmonitor diff --git a/translated/tech/20181004 Archiving web sites.md b/translated/tech/20181004 Archiving web sites.md deleted file mode 100644 index cca9ce3a09..0000000000 --- a/translated/tech/20181004 Archiving web sites.md +++ /dev/null @@ -1,119 +0,0 @@ -存档网站 -====== - -我最近深入研究了网站存档，因为有些朋友担心遇到糟糕的系统管理或恶意入侵时失去对在线托管的工作的控制。这使得网站存档成为任意系统管理员工具箱中的重要工具。事实证明，有些网站比其他网站更难存档。本文介绍了对传统网站进行存档的过程，并阐述在面对最新流行的单页面应用程序的现代网站时，它有哪些不足。 - -### 转换为简单网站 - -手动开发 HTML 网站的日子早已不复存在。现在的网站是动态的，并使用最新的 JavaScript，PHP 或 Python 框架即时构建。结果，这些网站更加脆弱：数据库崩溃，升级出错或者未修复的漏洞都可能使数据丢失。在我以前是一名 Web 开发人员时，我不得不接受客户希望网站基本上可以永久工作的想法。这种期望与 web 开发“快速行动和破除陈规”的理念不相符。在这方面，使用 [Drupal][2] 内容管理系统（CMS）尤其具有挑战性，因为重大更新会破坏与第三方模块的兼容性，这意味着客户很少承担的起高昂的升级成本。解决方案是将这些网站存档：以实时动态的网站为基础，将其转换为任何 web 服务器可以永久服务的纯 HTML 文件。此过程对你自己的动态网站非常有用，也适用于你想保护但无法控制的第三方网站。 - -对于简单的静态网站，古老的 [Wget][3] 程序就可以胜任。然而，镜像保存一个完整页面的方法，虽然复杂但很固定： - -``` - $ nice wget --mirror --execute robots=off --no-verbose --convert-links \ - --backup-converted --page-requisites --adjust-extension \ - --base=./ --directory-prefix=./ --span-hosts \ - --domains=www.example.com,example.com http://www.example.com/ - -``` - -以上命令下载了网页的内容，但也抓取了指定域名中的所有内容。在对你喜欢的网站执行此操作之前，请考虑此类抓取可能对网站产生的影响。上面的命令故意忽略了 `robots.txt` 规则，就像现在[档案管理者的习惯做法][4]，并尽可能快的存档网站。大多数抓取工具都可以选择点击暂停并限制带宽使用，以避免使网站瘫痪。 - -上面的命令还将获取 “page requisites（译者注：单页面所需的所有元素）”，像样式表（CSS），图像和脚本等。下载的页面内容将会被修改，以便链接也指向本地副本。任意 web 服务器均可托管生成的文件集，从而生成原始网站的静态副本。 - -以上所述是事情一切顺利的时候。任意使用过计算机的人都知道事情的进展很少如计划那样；各种各样的事情可以使程序以有趣的方式脱离正规。比如，在网站上有一个日历块很流行。内容管理系统会动态生成这些内容，这会使爬虫程序陷入死循环以尝试检索所有页面。灵巧的存档者可以使用正则表达式（例如 Wget 有一个 `--reject-regex` 选项）来忽略有问题的资源。如果可以访问网站的管理界面，另一个方法是禁用日历、登录表单、评论表单和其他动态区域。一旦网站变成静态的，（那些动态区域）也肯定会停止工作，因此从原始网站中移除这些杂乱的东西也不是全无意义。 - -### JavaScript 的厄运 - -很不幸，有些网站不仅仅是纯 HTML 文件构建的。比如，在单页面网站中，web 浏览器通过执行一个小的 JavaScript 程序来构建内容。像 Wget 这样的简单用户代理将难以重建这些网站的有意义的静态副本，因为它根本不支持 JavaScript。理论上，网站应该使用[渐进增强][5]技术，在不使用 JavaScript 的情况下提供内容和实现功能，但这些指示很少被遵循，因为使用 [NoScript][6] 或 [uMatrix][7] 等插件的人都很确定。 - -传统的存档方法有时是最愚蠢的方式，会导致失败。在尝试为一个本地报纸网站（[pamplemousse.ca][8]）创建备份时，我发现 WordPress 在末尾包含 JavaScript，且添加了查询字符串（例如：`?ver=1.12.4`）。这会使提供存档服务的 web 服务器不能正确进行内容类型检测，因为其靠文件扩展名来发送正确的 `Content-Type` 头部信息。在 web 浏览器加载此类存档时，这些脚本将无法加载，导致动态网站受损。 - -随着 web 向使用浏览器作为虚拟机执行任意代码转化，依赖于纯 HTML 文件解析的存档方法也需要随之适应。这个问题的解决方案是在抓取时记录（以及重现）服务器提供的 HTTP 头部信息，实际上专业的档案管理者就使用这种方法。 - -### 创建和显示 WARC 文件Creating and displaying WARC files - -在 [Internet Archive][9] 网站，Brewster Kahle 和 Mike Burner 在 1996 年设计了 [ARC][10] （用于 "ARChive"）文件格式，以提供一种聚合档案工作产生的百万个小文件的方法。该格式最终标准化为 WARC（“Web ARChive”）[规范][11]，并在 2009 年作为 ISO 标准发布，2017 年修订。标准化工作由[国际互联网保护联盟][12]（IIPC）领导，据维基百科称，这是一个“为共同保护未来互联网内容而建立的图书馆和国际组织”；它有美国国会图书馆和互联网档案馆等成员。后者内部在其基于 Java 的 [Heritrix crawler][13]（译者注：一种爬虫程序）上使用 WARC 格式。 - -WARC 在单个压缩文件中聚合了多种资源，像 HTTP 头部信息，文件内容，以及其他元数据。方便的是实际上 Wget 提供了 `--warc` 参数来支持 WARC 格式。不幸的是 web 浏览器不能直接显示 WARC 文件，所以为了访问存档文件，一个查看器或某些格式转换是很有必要的。我所发现的最简单的查看器是 [pywb][14]，它以 Python 包的形式运行一个简单的 web 服务器提供一个像网站时光倒流机网站的界面，来浏览 WARC 文件的内容。执行以下命令将会在 `http://localhost:8080/` 地址显示 WARC 文件的内容： - -``` - $ pip install pywb - $ wb-manager init example - $ wb-manager add example crawl.warc.gz - $ wayback - -``` - -顺便说一句，这个工具是由 [Webrecorder][15] 服务提供者建立的，Webrecoder 服务可以使用 web 浏览器保存动态页面的内容。 - -很不幸，pywb 无法加载 Wget 生成的 WARC 文件，因为它[遵循][16][不一致的 1.0 规范][17]，[1.1 规范修复了此问题][17]。就算 Wget 或 pywb 修复了这些问题，Wget 生成的 WARC 文件对我的使用来说不够可靠，所以我找了其他的替代品。引起我注意的爬虫程序简称 [crawl][19]。以下是它的调用方式： - -``` - $ crawl https://example.com/ - -``` - -（它的 README 文件说“非常简单”。）该程序确实支持一些命令行参数选项，但大多数默认值都是最佳的：它会从其他域获取页面需求（除非使用 `-exclude-related` 参数），但肯定不会递归出域。默认情况下，它会与远程站点建立十个并发连接，这个值可以使用 `-c` 参数更改。但是，最重要的是，生成的 WARC 文件可以使用 pywb 完美加载。 - -### 未来的工作和替代方案 - -这里还有更多有关使用 WARC 文件的[资源][20]。特别要提的是，这里有一个专门用来存档网站的 Wget 的直接替代品，叫做 [Wpull][21]。它实验性地支持了 [PhantomJS][22] 和 [youtube-dl][23] 的集成，即允许分别下载更复杂的 JavaScript 页面以及流媒体。该程序是一个叫做 [ArchiveBot][24] 的复杂档案工具的基础，ArchiveBot 被那些在 [ArchiveTeam][25] 的“零散离群的档案管理者、程序员、作家以及演说家”使用，他们致力于“在历史永远丢失之前保存他们”。集成 PhantomJS 好像并没有如团队期望的那样良好工作，所以 ArchiveTeam 也用其他的低等工具来镜像保存更复杂的网站。例如，[snscrape][26] 将抓取社交媒体配置文件以生成要发送到 ArchiveBot 的页面列表。团队使用的另一个工具是 [crocoite][27]，它在 Chrome 浏览器下以无头文件信息的模式来存档 JavaScript 较多的网站。 - -如果没有提到称做“网站复制者”的 [HTTrack][28] 项目，那么这篇文章算不上完整。工作方式和 Wget 相似，HTTrack 可以对远程站点创建一个本地的副本，但是不幸的是它不支持输出 WRAC 文件。对于不熟悉命令行的小白用户来说，它在人机交互方面显得更有价值。 - -同样，在我的研究中，我发现了叫做 [Wget2][29] 的 Wget 的完全重制版本，它支持多线程操作，这可能使它比前身更快。和 Wget 相比，它[舍弃了一些功能][30]，但是最值得注意的是拒绝模式、WARC 输出以及 FTP 支持，并增加了 RSS、DNS 缓存以及改进的 TLS 支持。 - -最后，我个人对这些工具的愿景是将他们与现有的书签系统集成起来。目前我在 [Wallabag][31] 中保留了一些有趣的链接，这是一种自托管式的“稍后阅读”服务，意在成为 [Pocket][32]（现在由 Mozilla 拥有）的免费替代品。但是 Wallabag 在设计上只保留了文章的“可读”副本，而不是一个完整的拷贝。在某些情况下，“可读版本”实际上[不可读][33]，并且 Wallabag 有时[无法解析文章][34]。恰恰相反，像 [bookmark-archiver][35] 或 [reminiscence][36] 这样其他的工具会保存页面的屏幕截图以及完整的 HTML 文件，但遗憾的是，它没有 WRAC 文件所以没有办法更可信的重现网页内容。 - -我所经历的有关镜像保存和存档的悲剧就是死数据。幸运的是，业余档案管理者可以利用工具将有趣的内容保存到网上。对于那些不想麻烦的人来说，互联网档案馆依然要留在这里，并且存档团队显然[正在为互联网档案馆本身做备份][37]。 - --------------------------------------------------------------------------------- - -via: https://anarc.at/blog/2018-10-04-archiving-web-sites/ - -作者：[Anarcat][a] -选题：[lujun9972](https://github.com/lujun9972) -译者：[fuowang](https://github.com/fuowang) -校对：[校对者ID](https://github.com/校对者ID) - -本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 - -[a]: https://anarc.at -[1]: https://anarc.at/blog -[2]: https://drupal.org -[3]: https://www.gnu.org/software/wget/ -[4]: https://blog.archive.org/2017/04/17/robots-txt-meant-for-search-engines-dont-work-well-for-web-archives/ -[5]: https://en.wikipedia.org/wiki/Progressive_enhancement -[6]: https://noscript.net/ -[7]: https://github.com/gorhill/uMatrix -[8]: https://pamplemousse.ca/ -[9]: https://archive.org -[10]: http://www.archive.org/web/researcher/ArcFileFormat.php -[11]: https://iipc.github.io/warc-specifications/ -[12]: https://en.wikipedia.org/wiki/International_Internet_Preservation_Consortium -[13]: https://github.com/internetarchive/heritrix3/wiki -[14]: https://github.com/webrecorder/pywb -[15]: https://webrecorder.io/ -[16]: https://github.com/webrecorder/pywb/issues/294 -[17]: https://github.com/iipc/warc-specifications/issues/23 -[18]: https://github.com/iipc/warc-specifications/pull/24 -[19]: https://git.autistici.org/ale/crawl/ -[20]: https://archiveteam.org/index.php?title=The_WARC_Ecosystem -[21]: https://github.com/chfoo/wpull -[22]: http://phantomjs.org/ -[23]: http://rg3.github.io/youtube-dl/ -[24]: https://www.archiveteam.org/index.php?title=ArchiveBot -[25]: https://archiveteam.org/ -[26]: https://github.com/JustAnotherArchivist/snscrape -[27]: https://github.com/PromyLOPh/crocoite -[28]: http://www.httrack.com/ -[29]: https://gitlab.com/gnuwget/wget2 -[30]: https://gitlab.com/gnuwget/wget2/wikis/home -[31]: https://wallabag.org/ -[32]: https://getpocket.com/ -[33]: https://github.com/wallabag/wallabag/issues/2825 -[34]: https://github.com/wallabag/wallabag/issues/2914 -[35]: https://pirate.github.io/bookmark-archiver/ -[36]: https://github.com/kanishka-linux/reminiscence -[37]: http://iabak.archiveteam.org diff --git a/translated/tech/20181025 How to write your favorite R functions in Python.md b/translated/tech/20181025 How to write your favorite R functions in Python.md new file mode 100644 index 0000000000..39c14e06d9 --- /dev/null +++ b/translated/tech/20181025 How to write your favorite R functions in Python.md @@ -0,0 +1,147 @@ +如何在 Python 中写你喜爱的 R 函数 +====== +R 还是 Python ? 这个 Python 脚本模仿方便的 R 风格函数，使统计数据变得简单易行。 + + + +“Python vs. R” 是数据科学和机器学习的现代战争之一。毫无疑问，近年来两者发展迅猛并成为数据科学，预测分析和机器学习领域的顶级编程语言。事实上，根据 IEEE 最近一篇文章，Python 已在 [最受欢迎编程语言排行榜][1] 中超越 C++ 并且 R 语言也稳居前 10 位。 + +但是，这两者之间存在一些根本区别。[R] 主要作为统计分析和数据分析问题的快速原型设计的工具而开发的。另一方面，Python 开发为一种通用的，现代的面向对象语言，类似 C++ 或 Java，但具有更简单的学习曲线和更灵活的语言风格。因此，R 仍在统计学家，定量生物学家，物理学家和经济学家中备受青睐，而 Python 已逐渐成为日常脚本，自动化，后端Web开发，分析和通用机器学习框架的顶级语言并拥有广泛的支持基础和开源开发社区。 + +###在 Python 环境中模仿函数式编程 + +[R] 作为函数式编程语言的天性为用户提供了一个极其简单和紧凑的借口，用于快速计算概率和数据分析问题的基本描述/推论统计。例如，只用一个紧凑的函数调用来解决以下问题难道不是很好吗？ + + * 如何计算数据向量的均值 / 中值 / 众数。 + * 如何计算某些服从正态分布事件的累积概率。如果服从 Poisson 分布会怎样？ + * 如何计算一系列数据点的四分差。 + * 如何生成服从学生 t 分布的一些随机数。 + +R编程环境可以完成所有这些工作。 + +另一方面，Python的脚本编写能力使分析师能够在各种分析流程中使用这些统计数据，具有无限的复杂性和创造力。 + +要结合二者的优势，您只需要一个简单的基于 Python 的包装器库，其中包含与 R 风格定义的概率分布和描述性统计相关的最常用函数。 这使您可以非常快速地调用这些函数，而无需转到正确的 Python 统计库并理解整个方法和参数列表。 + + +### 便于调用 R 函数的 Python 包装脚本 + +[我编写了一个Python脚本] [4] 在 Python 中定义了简单统计分析中方便广泛使用的 R 函数。 + +此脚本的目标是提供简单的 Python 子例程，模仿 R 风格的统计函数，以快速计算密度/点估计，累积分布和分位数，并生成重要概率分布的随机变量。 + +为了保持 R 风格的精髓，脚本不使用类层次结构，并且只在文件中定义原始函数。 因此，用户可以导入这个 Python 脚本，并在需要单个名称调用时使用所有功能。 + +请注意，我使用 mimic 这个词。 在任何情况下，我都声称要模仿 R 的真正的函数式编程范例，该范式包括深层环境设置以及这些环境和对象之间的复杂关系。 这个脚本允许我（我希望无数其他 Python 用户）快速启动P ython 程序或 Jupyter 笔记本，导入脚本，并立即开始进行简单的描述性统计。 这就是目标，仅此而已。 + +如果您已经写过 R 代码（可能在研究生院）并且刚刚开始学习并使用 Python 进行数据分析，那么您将很高兴看到并在 Jupyter 笔记本中以类似在 R 环境中一样使用一些相同的知名函数。 + +无论出于何种原因，使用这个脚本很有趣。 + +### 简单的例子 + +首先，只需导入脚本并开始处理数字列表，就好像它们是 R 中的数据向量一样。 + +``` +from R_functions import * +lst=[20,12,16,32,27,65,44,45,22,18] + +``` + +假设您想从数据点向量计算[Tuckey五数] [5]摘要。 你只需要调用一个简单的函数 ** fivenum **，然后传递向量。 它将返回 NumPy 数组中的五数摘要。 + +``` +lst=[20,12,16,32,27,65,44,45,22,18] +fivenum(lst) +> array([12. , 18.5, 24.5, 41. , 65. ]) +``` + +或许你想要知道下面问题的解答 + +假设一台机器平均每小时输出 10 件成品，标准偏差为 2。输出模式遵循接近正态的分布。 机器在下一个小时内输出至少 7 个但不超过 12 个单位的概率是多少？ + +答案基本上是这样的： + + + +您可以使用 **pnorm** 只用一行代码获得答案： + +``` +pnorm(12,10,2)-pnorm(7,10,2) +> 0.7745375447996848 +``` +或者您可能需要回答以下问题： + +假设你有一个不正的硬币，每次投它时有 60％ 可能正面朝上。 你正在玩10次投掷游戏。 你如何绘制并给出这枚硬币所有可能的胜利数（从0到10）？ + +只需使用一个函数 **dbinom** 就可以获得一个只有几行代码的漂亮条形图： + +``` +probs=[] +import matplotlib.pyplot as plt +for i in range(11): + probs.append(dbinom(i,10,0.6)) +plt.bar(range(11),height=probs) +plt.grid(True) +plt.show() +``` + + + +### 简单概率计算接口 + +R 提供了一个非常简单直观的界面，可以从基本概率分布中快速计算。 接口如下： + +* **d** {distribution} 给出点 **x** 处的密度函数值 +* **p** {distribution} 给出 **x**点的累积值 +* **q** {distribution} 以概率 **p**给出分位数函数值 +* **r** {distribution} 生成一个或多个随机变量 + +在我们的实现中，我们坚持使用此接口及其关联的参数列表，以便您可以像在 R 环境中一样执行这些函数。 + +### 目前实现的函数 + +脚本中实现了以下R风格函数，以便快速调用。 + + * 均值，中位数，方差，标准差 + * Tuckey 五数总结，IQR + * 矩阵的协方差或两个向量之间的协方差 + * 以下分布的密度，累积概率，分位数函数和随机变量生成：正态，均匀，二项式，泊松，F，学生t，卡方，β和伽马 + +### 进行中的工作 + +显然，这是一项正在进行的工作，我计划在此脚本中添加一些其他方便的R函数。 例如，在 R 中，单行命令 ** lm ** 可以为数字数据集提供一个普通的最小二乘拟合模型，其中包含所有必要的推理统计量（P 值，标准误差等）。 这是有力的简洁和紧凑！ 另一方面，Python 中的标准线性回归问题经常使用 [Scikit-learn] [6] 来处理，这需要更多的脚本用于此用途，所以我打算使用 Python 的 [statsmodels] 合并这个单函数线性模型拟合特征 [7]后端。 + +如果您喜欢并在工作中使用此脚本，请通过主演或分析其 [GitHub存储库] [8]帮助其他人找到它。 另外，您可以查看我的其他 [GitHub repos] [9]，了解 Python，R 或 MATLAB 中的有趣代码片段以及一些机器学习资源。 + +如果您有任何问题或想法要分享，请通过 [tirthajyoti [AT] gmail.com] [10]与我联系。 如果你像我一样热衷于机器学习和数据科学，请 [加我在LinkedIn] [11]或[在Twitter上关注我。] [12] + +最初发表于[走向数据科学] [13]。 转载于[CC BY-SA 4.0] [14]。 + +-------------------------------------------------------------------------------- + +via: https://opensource.com/article/18/10/write-favorite-r-functions-python + +作者：[Tirthajyoti Sarkar][a] +选题：[lujun9972][b] +译者：[yongshouzhang](https://github.com/yongshouzhang) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]: https://opensource.com/users/tirthajyoti +[b]: https://github.com/lujun9972 +[1]: https://spectrum.ieee.org/at-work/innovation/the-2018-top-programming-languages +[2]: https://www.coursera.org/lecture/r-programming/overview-and-history-of-r-pAbaE +[3]: http://adv-r.had.co.nz/Functional-programming.html +[4]: https://github.com/tirthajyoti/StatsUsingPython/blob/master/R_Functions.py +[5]: https://en.wikipedia.org/wiki/Five-number_summary +[6]: http://scikit-learn.org/stable/ +[7]: https://www.statsmodels.org/stable/index.html +[8]: https://github.com/tirthajyoti/StatsUsingPython +[9]: https://github.com/tirthajyoti?tab=repositories +[10]: mailto:tirthajyoti@gmail.com +[11]: https://www.linkedin.com/in/tirthajyoti-sarkar-2127aa7/ +[12]: https://twitter.com/tirthajyotiS +[13]: https://towardsdatascience.com/how-to-write-your-favorite-r-functions-in-python-11e1e9c29089 +[14]: https://creativecommons.org/licenses/by-sa/4.0/ diff --git a/translated/tech/20181119 9 obscure Python libraries for data science.md b/translated/tech/20181119 9 obscure Python libraries for data science.md new file mode 100644 index 0000000000..ec9cab2858 --- /dev/null +++ b/translated/tech/20181119 9 obscure Python libraries for data science.md @@ -0,0 +1,268 @@ + +9个不为人知晓的Python数据科学库 +====== + +除了 pandas 、scikit-learn 和 matplotlib，还要学习一些用 Python 进行数据科学的新技巧。 + + + + +Python 是一种令人惊叹的语言。事实上，它是世界上增长最快的编程语言之一。它一次又一次地证明了它在各个行业的开发者和数据科学者中的作用。Python 及其库的整个生态系统使其成为全世界用户(初学者和高级用户)的恰当选择。它成功和受欢迎的原因之一是它的一组强大的库，使它如此动态和快速。 + +在本文中，我们将看到 Python 库中的一些数据科学工具，而不是那些常用的工具，如 **pandas,scikit-learn** ,和 **matplotlib** 。虽然像 **pandas,scikit-learn** 这样的库是机器学习中最常想到的，但是了解这个领域的其他 Python 产品库也是非常有帮助的。 + +### Wget + +提取数据，尤其是从网络中提取数据，是数据科学家的重要任务之一。[Wget][1] 是一个免费的工具，用于从网络上非交互式下载文件。它支持 HTTP、HTTPS 和 FTP 协议，以及通过 HTTP 代理进行检索。因为它是非交互式的，所以即使用户没有登录，它也可以在后台工作。所以下次你想下载一个网站或者网页上的所有图片，**wget** 会提供帮助。 + +#### 安装 + +``` +$ pip install wget +``` + +#### 例子 + +``` +import wget +url = 'http://www.futurecrew.com/skaven/song_files/mp3/razorback.mp3' + +filename = wget.download(url) +100% [................................................] 3841532 / 3841532 + +filename +'razorback.mp3' +``` + +### 钟摆 + +对于在 Python 中处理时间感到沮丧的人来说， **[Pendulum][2]** 库是很有帮助的。这是一个 Python 包，可以简化 **datetime** 操作。它是 Python 原生类的一个替换。有关详细信息，请参阅[documentation][3]。 + + +#### 安装 + +``` +$ pip install pendulum +``` + +#### 例子 + +``` +import pendulum + +dt_toronto = pendulum.datetime(2012, 1, 1, tz='America/Toronto') +dt_vancouver = pendulum.datetime(2012, 1, 1, tz='America/Vancouver') + +print(dt_vancouver.diff(dt_toronto).in_hours()) + +3 +``` + +### 不平衡学习 + +当每个类别中的样本数几乎相同(即平衡)时，大多数分类算法会工作得最好。但是现实生活中的案例中充满了不平衡的数据集，这可能会影响到机器学习算法的学习和后续预测。幸运的是， **[imbalanced-learn][4]** 库就是为了解决这个问题而创建的。它与[**scikit-learn**][5] 兼容，并且是 **[scikit-learn-contrib][6]** 项目的一部分。下次遇到不平衡的数据集时，可以尝试一下。 + +#### 安装 + +``` +pip install -U imbalanced-learn + +# or + +conda install -c conda-forge imbalanced-learn +``` + +#### 例子 + +有关用法和示例，请参阅 [documentation][7] 。 + + +### 闪光灯文字 + +在自然语言处理( NLP )任务中清理文本数据通常需要替换句子中的关键词或从句子中提取关键词。通常，这种操作可以用正则表达式来完成，但是如果要搜索的术语数达到数千个，它们可能会变得很麻烦。 + +Python的 **[FlashText][8]** 模块，基于 [FlashText algorithm][9]算法，为这种情况提供了一个合适的替代方案。FlashText 的最佳部分是运行时间与搜索项的数量无关。你可以在 [documentation][10] 中读到更多关于它的信息。 + +#### 安装 + +``` +$ pip install flashtext +``` + +#### 例子 + +##### **提取关键词:** + +``` +from flashtext import KeywordProcessor +keyword_processor = KeywordProcessor() + +# keyword_processor.add_keyword( , ) + +keyword_processor.add_keyword('Big Apple', 'New York') +keyword_processor.add_keyword('Bay Area') +keywords_found = keyword_processor.extract_keywords('I love Big Apple and Bay Area.') + +keywords_found +['New York', 'Bay Area'] +``` + +**替代关键词:** + +``` +keyword_processor.add_keyword('New Delhi', 'NCR region') + +new_sentence = keyword_processor.replace_keywords('I love Big Apple and new delhi.') + +new_sentence +'I love New York and NCR region.' +``` + +For more examples, refer to the [usage][11] section in the documentation. + +有关更多示例，请参阅文档中的 [usage][11] 一节。 + +### 模糊处理 + +这个名字听起来很奇怪，但是 **[FuzzyWuzzy][12]** 在字符串匹配方面是一个非常有用的库。它可以很容易地实现字符串比较、令牌比较等操作。对于匹配保存在不同数据库中的记录也很方便。 + +#### 安装 + +``` +$ pip install fuzzywuzzy +``` + +#### 例子 + +``` +from fuzzywuzzy import fuzz +from fuzzywuzzy import process + +# 简单的匹配率 + +fuzz.ratio("this is a test", "this is a test!") +97 + +# 部分的匹配率 +fuzz.partial_ratio("this is a test", "this is a test!") + 100 +``` + +更多的例子可以在 FuzzyWuzy 的 [GitHub repo.][12]得到。 + +### PyFlux + +时间序列分析是机器学习中最常遇到的问题之一。**[PyFlux][13]** 是Python中的开源库，专门为处理时间序列问题而构建的。该库拥有一系列优秀的现代时间序列模型，包括但不限于 **ARIMA** 、 **GARCH** ,、以及**VAR**模型。简而言之，PyFlux 为时间序列建模提供了一种概率方法。这值得一试。 + +#### 安装 + +``` +pip install pyflux +``` + +#### 例子 + +有关用法和示例，请参阅 [documentation][14]。 + +### IPyvolume + + +交流结果是数据科学的一个重要方面，可视化结果提供了显著优势。 **[**IPyvolume**][15]** 是一个Python库，用于在Jupyter笔记本中可视化3D体积和字形(例如3D散点图)，配置和工作量极小。然而，它目前处于1.0之前的阶段。一个很好的类比是这样的: IPyVolumee **volshow** 是3D阵列，Matplotlib 的**imshow** 是2D阵列。你可以在 [documentation][16] 中读到更多关于它的信息。 + +#### 安装 + +``` +Using pip +$ pip install ipyvolume + +Conda/Anaconda +$ conda install -c conda-forge ipyvolume +``` + +#### 例子 + +**Animation:** + + +**Volume rendering:** + + +### Dash + +**[Dash][17]** 是一个用于构建 Web 应用程序的高效 Python 框架。它写在Flask、Plotty.js和Response.js 的顶部，将下拉菜单、滑块和图形等流行 UI 元素与分析 Python 代码联系起来，而不需要JavaScript。Dash 非常适合构建可在 Web 浏览器中呈现的数据可视化应用程序。有关详细信息，请参阅 [user guide][18] 。 + +#### 安装 + +``` +pip install dash==0.29.0 # The core dash backend +pip install dash-html-components==0.13.2 # HTML components +pip install dash-core-components==0.36.0 # Supercharged components +pip install dash-table==3.1.3 # Interactive DataTable component (new!) +``` + +#### 例子 + + +下面的示例显示了一个具有下拉功能的高度交互的图表。当用户在下拉列表中选择一个值时，应用程序代码将数据从Google Finance 动态导出到 Pandas 数据框架中。 + + +### Gym + +从[OpenAI][20] 而来的 **[Gym][19]** 是开发和比较强化学习算法的工具包。它与任何数值计算库兼容，如TensorFlow 或Theano 。Gym 是一个测试问题的集合，也称为环境，你可以用它来制定你的强化学习算法。这些环境有一个共享接口，允许您编写通用算法。 + +#### 安装 + +``` +pip install gym +``` + +#### 例子 + + + +以下示例将在 **[CartPole-v0][21]** 环境中，运行1，000次，在每一步渲染环境。 + + +You can read about [other environments][22] on the Gym website. +你可以在 Gym 网站上读到其他的 [other environments][22] 。 + +### 结论 + +这些是我挑选的有用但鲜为人知的数据科学 Python 库。如果你知道另一个要添加到这个列表中，请在下面的评论中提及。 +这本书最初发表在 [Analytics Vidhya][23] 的媒体频道上，并经许可转载。 + + +via: https://opensource.com/article/18/11/python-libraries-data-science + +作者：[Parul Pandey][a] +选题：[lujun9972][b] +译者：[heguangzhi](https://github.com/heguangzhi) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]: https://opensource.com/users/parul-pandey +[b]: https://github.com/lujun9972 +[1]: https://pypi.org/project/wget/ +[2]: https://github.com/sdispater/pendulum +[3]: https://pendulum.eustace.io/docs/#installation +[4]: https://github.com/scikit-learn-contrib/imbalanced-learn +[5]: http://scikit-learn.org/stable/ +[6]: https://github.com/scikit-learn-contrib +[7]: http://imbalanced-learn.org/en/stable/api.html +[8]: https://github.com/vi3k6i5/flashtext +[9]: https://arxiv.org/abs/1711.00046 +[10]: https://flashtext.readthedocs.io/en/latest/ +[11]: https://flashtext.readthedocs.io/en/latest/#usage +[12]: https://github.com/seatgeek/fuzzywuzzy +[13]: https://github.com/RJT1990/pyflux +[14]: https://pyflux.readthedocs.io/en/latest/index.html +[15]: https://github.com/maartenbreddels/ipyvolume +[16]: https://ipyvolume.readthedocs.io/en/latest/?badge=latest +[17]: https://github.com/plotly/dash +[18]: https://dash.plot.ly/ +[19]: https://github.com/openai/gym +[20]: https://openai.com/ +[21]: https://gym.openai.com/envs/CartPole-v0 +[22]: https://gym.openai.com/ +[23]: https://medium.com/analytics-vidhya/python-libraries-for-data-science-other-than-pandas-and-numpy-95da30568fad diff --git a/translated/tech/20181124 How To Configure IP Address In Ubuntu 18.04 LTS.md b/translated/tech/20181124 How To Configure IP Address In Ubuntu 18.04 LTS.md new file mode 100644 index 0000000000..2a97638b8a --- /dev/null +++ b/translated/tech/20181124 How To Configure IP Address In Ubuntu 18.04 LTS.md @@ -0,0 +1,137 @@ +[#]: collector: (lujun9972) +[#]: translator: (chenxinlong) +[#]: reviewer: ( ) +[#]: publisher: ( ) +[#]: subject: (How To Configure IP Address In Ubuntu 18.04 LTS) +[#]: via: (https://www.ostechnix.com/how-to-configure-ip-address-in-ubuntu-18-04-lts/) +[#]: author: (SK https://www.ostechnix.com/author/sk/) +[#]: url: ( ) + +如何在 Ubuntu 18.04 LTS 中配置 IP 地址 +====== + + + + +在 Ubuntu 18.04 LTS 中配置 IP 地址的方法和以往使用的配置方法有很大的不同。和旧版本的不同之处在于，Ubuntu 18.04 使用 **Netplan** 来配置 IP 地址，**Netplan** 是一个新的命令行网络配置工具。其实在 Ubuntu 17.10 的时候 Ubuntu 开发者就已经介绍过 Netplan 了。接下来要介绍的新的 IP 配置方法不会再用到 **/etc/network/interfaces** 这个文件，取而代之的是一个 YAML 文件。默认的 Netplan 配置文件一般在 **/etc/netplan** 目录下。 在这篇教程中，我们会去学习在 **Ubuntu 18.04 LTS** 的最小版本中配置静态 IP 和动态 IP 。 + +### 在 Ubuntu 18.04 LTS 中配置静态 IP 地址 + +首先先找到 Netplan 默认的网络配置文件所在之处： + +``` +$ ls /etc/netplan/ +50-cloud-init.yaml +``` + +我们可以看到，默认的网络配置文件是 **50-cloud-init.yaml** ，这是一个 YAML 文件。 + +然后我们再看一下这个文件的内容是什么： + +``` +$ cat /etc/netplan/50-cloud-init.yaml +``` + +我在之前安装 Ubuntu 18.04 的时候为了从 DHCP 服务器获取 IP 地址已经已经做过了网卡的相关配置，所以详细配置直接看下图： + + + +可以看到这边有两个网卡，分别是 **enp0s3** 和 **enp0s8** ，并且这两个网卡都配置为从 DHCP 服务器中获取 IP。 + +现在我们给这两个网卡都配置为静态 IP 地址，先用任意一种编辑器来编辑配置文件。 + +``` +$ sudo nano /etc/netplan/50-cloud-init.yaml +``` + +接下来我们分别添加 IP 地址、子网掩码、网关、DNS 服务器等配置。分别用 **192.168.225.50** 作为网卡 **enp0s3** 的 IP 地址， **192.168.225.51** 作为网卡 **enp0s8** 的 IP 地址， **192.168.225.1** 作为网关地址， **255.255.255.0** 作为子网掩码。然后用 **8.8.8.8** 、 **8.8.4.4** 这两个 DNS 服务器 IP。 + + + + +要注意的一点是，在 Ubuntu 18.04 里，这个配置文件的每一行都必须靠空格来缩进，不能用 **TAB** 来代替，否则配置会不起作用。如上图所示的配置文件中每行的缩进都是靠空格键实现的。 + +同时，在 Ubuntu 18.04 中，我们定义子网掩码的时候不是像旧版本的那样把 IP 和子网掩码分成两项配置。在旧版本的 Ubuntu 里，我们一般配置的 IP 和子网掩码是这样的： + +``` +address = 192.168.225.50 +netmask = 255.255.255.0 +``` + +而在 netplan 中，我们把这两项合并成一项，就像这样： + +``` +addresses : [192.168.225.50/24] +``` + +配置完成之后保存并关闭配置文件。然后用下面这行命令来应用刚才的配置： + +``` +$ sudo netplan apply +``` + +如果在应用配置的时候有出现问题的话，可以通过如下的命令来查看刚才配置的内容出了什么问题。 + +``` +$ sudo netplan --debug apply +``` + +这行命令会输出这些 debug 信息： + +``` +** (generate:1556): DEBUG: 09:14:47.220: Processing input file //etc/netplan/50-cloud-init.yaml.. +** (generate:1556): DEBUG: 09:14:47.221: starting new processing pass +** (generate:1556): DEBUG: 09:14:47.221: enp0s8: setting default backend to 1 +** (generate:1556): DEBUG: 09:14:47.222: enp0s3: setting default backend to 1 +** (generate:1556): DEBUG: 09:14:47.222: Generating output files.. +** (generate:1556): DEBUG: 09:14:47.223: NetworkManager: definition enp0s8 is not for us (backend 1) +** (generate:1556): DEBUG: 09:14:47.223: NetworkManager: definition enp0s3 is not for us (backend 1) +DEBUG:netplan generated networkd configuration exists, restarting networkd +DEBUG:no netplan generated NM configuration exists +DEBUG:device enp0s3 operstate is up, not replugging +DEBUG:netplan triggering .link rules for enp0s3 +DEBUG:device lo operstate is unknown, not replugging +DEBUG:netplan triggering .link rules for lo +DEBUG:device enp0s8 operstate is up, not replugging +DEBUG:netplan triggering .link rules for enp0s8 +``` + +如果配置正常且生效的话，我们可以用下面这个命令来查看一下 ip： + +``` +$ ip addr +``` + +在我的 Ubuntu 18.04 中配置完之后执行命令输出的信息如下： + + + +到此为止，我们已经成功地在 Ubuntu 18.04 LTS 中用 Netplan 完成了静态 IP 的配置。 + +更多关于 Netplan 的信息，可以在用 man 命令在手册中查看： + +``` +$ man netplan +``` + +### 在 Ubuntu 18.04 LTS 中配置动态 IP 地址 + +其实配置文件中的初始配置就是动态 IP 的配置，所以你想要使用动态 IP 的话不需要再去做任何的配置操作。如果你已经配置了静态 IP 地址，想要恢复之前动态 IP 的配置，就把在上面静态 IP 配置中所添加的相关配置项删除，把整个配置文件恢复成上面的图 1 所示的样子就行了。 + +现在你已经学会在 Ubuntu 18.04 中配置静态和动态 IP 地址了。个人而言，我 (原作者) 其实不太喜欢这种方式，旧的配置方式反而来得简单。你们觉得呢 ？ + + + +-------------------------------------------------------------------------------- + +via: https://www.ostechnix.com/how-to-configure-ip-address-in-ubuntu-18-04-lts/ + +作者：[SK][a] +选题：[lujun9972][b] +译者：[chenxinlong](https://github.com/chenxinlong) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]: https://www.ostechnix.com/author/sk/ +[b]: https://github.com/lujun9972 diff --git a/选题模板.txt b/选题模板.txt index a7cd92e614..4515fe78ab 100644 --- a/选题模板.txt +++ b/选题模板.txt @@ -1,43 +1,65 @@ -选题标题格式: +选题标题格式： - 原文日期 标题.md +``` +原文日期 标题.md +``` -正文内容: +其中： - 标题 - ======= - - ### 子一级标题 - - 正文 - - #### 子二级标题 - - 正文内容 - -  - - ### 子一级标题 - - 正文内容 ： I have a [dream][1]。 +- 原文日期为该文章发表时的日期，采用 8 位数字表示 +- 标题需去除特殊字符，使用 `_` 替换。 - -------------------------------------------------------------------------------- - - via: 原文地址 - - 作者：[作者名][a] - 译者：[译者ID](https://github.com/译者ID) - 校对：[校对者ID](https://github.com/校对者ID) - - 本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 - - [a]: 作者介绍地址 - [1]: 引文链接地址 +正文内容： -说明: -1. 标题层级很多时从 “##” 开始 -2. 引文链接地址在下方集中写 +``` +[#]: collector: (选题人 GitHub ID) +[#]: translator: ( ) +[#]: reviewer: ( ) +[#]: publisher: ( ) +[#]: subject: (文章标题) +[#]: via: (原文 URL) +[#]: author: (作者名 作者链接 URL) +[#]: url: ( ) + +标题 +======= + +### 子一级标题 + +正文 + +#### 子二级标题 + +正文内容 + +![][1] + +### 子一级标题 + +正文内容 ： I have a [dream][2]。 + +-------------------------------------------------------------------------------- + +via: 原文 链接 URL + +作者：[作者名][a] +译者：[选题 ID][b] +译者：[译者 ID](https://github.com/译者 ID) +校对：[校对 ID](https://github.com/校对 ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]: 作者链接 URL +[b]: 选题链接 URL +[1]: 图片链接地址 +[2]: 文内链接地址 +``` + +说明： + +1. 标题层级很多时从 `##` 开始 +2. 图片链接和引文链接地址在下方集中写 3. 因为 Windows 系统文件名有限制，所以文章名不要有特殊符号，如 `\/:*"<>|`，同时也不推荐全大写，或者其它不利阅读的格式 4. 正文格式参照中文排版指北(https://github.com/LCTT/TranslateProject/blob/master/%E4%B8%AD%E6%96%87%E6%8E%92%E7%89%88%E6%8C%87%E5%8C%97.md) -5. 我们使用的 markdown 语法和 github 一致，具体语法可参见 https://github.com/guodongxiaren/README 。而实际中使用的都是基本语法，比如链接、包含图片、标题、列表、字体控制和代码高亮。 +5. 我们使用的 markdown 语法和 GitHub 一致。而实际中使用的都是基本语法，比如链接、包含图片、标题、列表、字体控制和代码高亮。 6. 选题的内容分为两类： 干货和湿货。干货就是技术文章，比如针对某种技术、工具的介绍、讲解和讨论。湿货则是和技术、开发、计算机文化有关的文章。选题时主要就是根据这两条来选择文章，文章需要对大家有益处，篇幅不宜太短，可以是系列文章，也可以是长篇大论，但是文章要有内容，不能有严重的错误，最好不要选择已经有翻译的原文。
- ` 是 `
` 的子节点，`
` 已经被约束到 550px，所以 `
- ` 不会超出这个范围。
+
+让我们保存文件并刷新浏览器以查看结果：
+
+
+
+你会立即注意到在每个列表项之前显示了重点标志。我们现在不需要在每个列表项之前写 “-”。
+
+经过仔细检查，你会注意到最后一行超出 550px 宽度。这是为什么？因为 HTML 不允许 `
- ` 元素出现在 `
` 元素中。让我们将第一行和最后一行放在单独的 `
` 元素中： + +``` +
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you. +
+``` + +``` ++ You complete my darkness with your light. I love: +
+``` + +``` +-
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time. +
+``` + +保存并刷新。 + +注意，这次我们还定义了 `- ` 元素的宽度。那是因为我们现在已经将 `
- ` 元素放在了 `
` 元素之外。 + +定义情书中所有元素的宽度会变得很麻烦。我们有一个特定的元素用于此目的：`
` 元素。一个 `
` 元素就是一个通用容器，用于对内容进行分组，以便轻松设置样式。
+
+让我们用 `
` 元素包装整个情书，并为其赋予宽度：550px 。
+
+```
+`、`
+
+```
+
+棒极了，我们的代码现在看起来简洁多了。
+
+### HTML 中的标题
+
+到目前为止，蝙蝠侠对结果很高兴，他希望在情书上标题。他想写一个标题： “Bat Letter”。当然，你已经看到这个名字了，不是吗？:D
+
+你可以使用 `+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you. +
++ You complete my darkness with your light. I love: +
+-
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time. +
+`、``、``、``、`` 和 `` 标签来添加标题，`` 是最大的标题和最主要的标题，`` 是最小的标题。
+
+
+
+让我们在第二段之前使用 `` 做主标题和一个副标题：
+
+```
+
+ Bat Letter
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+
+```
+
+保存，刷新。
+
+
+
+### HTML 中的图像
+
+我们的情书尚未完成，但在继续之前，缺少一件大事：蝙蝠侠标志。你见过是蝙蝠侠的东西但没有蝙蝠侠的标志吗？
+
+并没有。
+
+所以，让我们在情书中添加一个蝙蝠侠标志。
+
+在 HTML 中包含图像就像在一个 Word 文件中包含图像一样。在 MS Word 中，你到 “菜单 -> 插入 -> 图像 -> 然后导航到图像位置为止 -> 选择图像 -> 单击插入”。
+
+在 HTML 中，我们使用 `![]()
` 标签让浏览器知道我们需要加载的图像，而不是单击菜单。我们在 `src` 属性中写入文件的位置和名称。如果图像在项目根目录中，我们可以简单地在 `src` 属性中写入图像文件的名称。
+
+在我们深入编码之前，从[这里][3]下载蝙蝠侠标志。你可能希望裁剪图像中的额外空白区域。复制项目根目录中的图像并将其重命名为 “bat-logo.jpeg”。
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+
+```
+
+我们在第 3 行包含了 `![]()
` 标签。这个标签也是一个自闭合的标签，所以我们不需要写 ``。在 `src` 属性中，我们给出了图像文件的名称。这个名称应与图像名称完全相同，包括扩展名（.jpeg）及其大小写。
+
+保存并刷新，查看结果。
+
+
+
+该死的！刚刚发生了什么？
+
+当使用 `![]()
` 标签包含图像时，默认情况下，图像将以其原始分辨率显示。在我们的例子中，图像比 550px 宽得多。让我们使用 `style` 属性定义它的宽度：
+
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+
+```
+
+你会注意到，这次我们定义宽度使用了 “%” 而不是 “px”。当我们在 “%” 中定义宽度时，它将占据父元素宽度的百分比。因此，100% 的 550px 将为我们提供 550px。
+
+保存并刷新，查看结果。
+
+
+
+太棒了！这让蝙蝠侠的脸露出了羞涩的微笑 :)。
+
+### HTML 中的粗体和斜体
+
+现在蝙蝠侠想在最后几段中承认他的爱。他有以下文本供你用 HTML 编写：
+
+“I have a confession to make
+
+It feels like my chest _does_ have a heart. You make my heart beat. Your smile brings a smile to my face, your pain brings pain to my heart.
+
+I don’t show my emotions, but I think this man behind the mask is falling for you.”
+
+当阅读到这里时，你会问蝙蝠侠：“等等，这是给谁的？”蝙蝠侠说：
+
+“这是给超人的。”
+
+
+
+你说：哦！我还以为是给神奇女侠的呢。
+
+蝙蝠侠说：不，这是给超人的，请在最后写上 “I love you Superman.”。
+
+好的，我们来写：
+
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+```
+
+这封信差不多完成了，蝙蝠侠另外想再做两次改变。蝙蝠侠希望在最后段落的第一句中的 “does” 一词是斜体，而 “I love you Superman” 这句话是粗体的。
+
+我们使用 `` 和 `` 以斜体和粗体显示文本。让我们来更新这些更改：
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+```
+
+
+
+### HTML 中的样式
+
+你可以通过三种方式设置样式或定义 HTML 元素的外观：
+
+* 内联样式：我们使用元素的 `style` 属性来编写样式。这是我们迄今为止使用的，但这不是一个好的实践。
+* 嵌入式样式：我们在由 `` 包裹的 “style” 元素中编写所有样式。
+* 链接样式表：我们在具有 .css 扩展名的单独文件中编写所有元素的样式。此文件称为样式表。
+
+让我们来看看如何定义 `` 的内联样式：
+
+```
+
+```
+
+我们可以在 `` 里面写同样的样式：
+
+```
+div{
+ width:550px;
+}
+```
+
+在嵌入式样式中，我们编写的样式是与元素分开的。所以我们需要一种方法来关联元素及其样式。第一个单词 “div” 就做了这样的活。它让浏览器知道花括号 `{...}` 里面的所有样式都属于 “div” 元素。由于这种语法确定要应用样式的元素，因此它称为一个选择器。
+
+我们编写样式的方式保持不变：属性（`width`）和值（`550px`）用冒号（`:`）分隔，以分号（`;`）结束。
+
+让我们从 `` 和 `![]()
` 元素中删除内联样式，将其写入 `
+```
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+```
+
+保存并刷新，结果应保持不变。
+
+但是有一个大问题，如果我们的 HTML 文件中有多个 `` 和 `![]()
` 元素该怎么办？这样我们在 `
+```
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+```
+
+HTML 已经准备好了嵌入式样式。
+
+但是，你可以看到，随着我们包含越来越多的样式，`` 将变得很大。这可能很快会混乱我们的主 HTML 文件。
+
+因此，让我们更进一步，通过将 ``。
+
+我们需要使用 HTML 文件中的 `` 标签来将新创建的 CSS 文件链接到 HTML 文件。以下是我们如何做到这一点：
+
+```
+
+```
+
+我们使用 `` 元素在 HTML 文档中包含外部资源，它主要用于链接样式表。我们使用的三个属性是：
+
+* `rel`：关系。链接文件与文档的关系。具有 .css 扩展名的文件称为样式表，因此我们保留 rel=“stylesheet”。
+* `type`：链接文件的类型；对于一个 CSS 文件来说它是 “text/css”。
+* `href`：超文本参考。链接文件的位置。
+
+link 元素的结尾没有 ``。因此，`` 也是一个自闭合的标签。
+
+```
+
+```
+
+如果只是得到一个女朋友，那么很容易：D
+
+可惜没有那么简单，让我们继续前进。
+
+这是我们 “loveletter.html” 的内容：
+
+```
+
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+```
+
+“style.css” 内容：
+
+```
+#letter-container{
+ width:550px;
+}
+#header-bat-logo{
+ width:100%;
+}
+```
+
+保存文件并刷新，浏览器中的输出应保持不变。
+
+### 一些手续
+
+我们的情书已经准备好给蝙蝠侠，但还有一些正式的片段。
+
+与其他任何编程语言一样，HTML 自出生以来（1990 年）经历过许多版本，当前版本是 HTML5。
+
+那么，浏览器如何知道你使用哪个版本的 HTML 来编写页面呢？要告诉浏览器你正在使用 HTML5，你需要在页面顶部包含 ``。对于旧版本的 HTML，这行不同，但你不需要了解它们，因为我们不再使用它们了。
+
+此外，在之前的 HTML 版本中，我们曾经将整个文档封装在 `` 标签内。整个文件分为两个主要部分：头部在 `` 里面，主体在 `` 里面。这在 HTML5 中不是必须的，但由于兼容性原因，我们仍然这样做。让我们用 ``, ``、 `` 和 `` 更新我们的代码：
+
+```
+
+
+
+
+
+
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+
+
+```
+
+主要内容在 `` 里面，元信息在 `` 里面。所以我们把 `` 保存在 `` 里面并加载 `` 里面的样式表。
+
+保存并刷新，你的 HTML 页面应显示与之前相同的内容。
+
+### HTML 的标题
+
+我发誓，这是最后一次改变。
+
+你可能已经注意到选项卡的标题正在显示 HTML 文件的路径：
+
+
+
+我们可以使用 `` 标签来定义 HTML 文件的标题。标题标签也像链接标签一样在 `<head>` 内部。让我们我们在标题中加上 “Bat Letter”：
+
+```
+<!DOCTYPE html>
+<html>
+<head>
+ <title>Bat Letter
+
+
+
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+
+
+```
+
+保存并刷新，你将看到在选项卡上显示的是 “Bat Letter” 而不是文件路径。
+
+蝙蝠侠的情书现在已经完成。
+
+恭喜！你用 HTML 制作了蝙蝠侠的情书。
+
+
+
+### 我们学到了什么
+
+我们学习了以下新概念：
+
+ * 一个 HTML 文档的结构
+ * 在 HTML 中如何写元素（``）
+ * 如何使用 style 属性在元素内编写样式（这称为内联样式，尽可能避免这种情况）
+ * 如何在 `` 中编写元素的样式（这称为嵌入式样式）
+ * 在 HTML 中如何使用 `` 在单独的文件中编写样式并链接它（这称为链接样式表）
+ * 什么是标签名称，属性，开始标签和结束标签
+ * 如何使用 id 属性为一个元素赋予 id
+ * CSS 中的标签选择器和 id 选择器
+
+我们学习了以下 HTML 标签：
+
+ * ``：用于段落
+ * `
`：用于换行
+ * `
`、`
`、``、`` 和 `` 标签来添加标题，`` 是最大的标题和最主要的标题，`` 是最小的标题。
+
+
+
+让我们在第二段之前使用 `` 做主标题和一个副标题：
+
+```
+
+ Bat Letter
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+
+```
+
+保存，刷新。
+
+
+
+### HTML 中的图像
+
+我们的情书尚未完成，但在继续之前，缺少一件大事：蝙蝠侠标志。你见过是蝙蝠侠的东西但没有蝙蝠侠的标志吗？
+
+并没有。
+
+所以，让我们在情书中添加一个蝙蝠侠标志。
+
+在 HTML 中包含图像就像在一个 Word 文件中包含图像一样。在 MS Word 中，你到 “菜单 -> 插入 -> 图像 -> 然后导航到图像位置为止 -> 选择图像 -> 单击插入”。
+
+在 HTML 中，我们使用 `![]()
` 标签让浏览器知道我们需要加载的图像，而不是单击菜单。我们在 `src` 属性中写入文件的位置和名称。如果图像在项目根目录中，我们可以简单地在 `src` 属性中写入图像文件的名称。
+
+在我们深入编码之前，从[这里][3]下载蝙蝠侠标志。你可能希望裁剪图像中的额外空白区域。复制项目根目录中的图像并将其重命名为 “bat-logo.jpeg”。
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+
+```
+
+我们在第 3 行包含了 `![]()
` 标签。这个标签也是一个自闭合的标签，所以我们不需要写 ``。在 `src` 属性中，我们给出了图像文件的名称。这个名称应与图像名称完全相同，包括扩展名（.jpeg）及其大小写。
+
+保存并刷新，查看结果。
+
+
+
+该死的！刚刚发生了什么？
+
+当使用 `![]()
` 标签包含图像时，默认情况下，图像将以其原始分辨率显示。在我们的例子中，图像比 550px 宽得多。让我们使用 `style` 属性定义它的宽度：
+
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+
+```
+
+你会注意到，这次我们定义宽度使用了 “%” 而不是 “px”。当我们在 “%” 中定义宽度时，它将占据父元素宽度的百分比。因此，100% 的 550px 将为我们提供 550px。
+
+保存并刷新，查看结果。
+
+
+
+太棒了！这让蝙蝠侠的脸露出了羞涩的微笑 :)。
+
+### HTML 中的粗体和斜体
+
+现在蝙蝠侠想在最后几段中承认他的爱。他有以下文本供你用 HTML 编写：
+
+“I have a confession to make
+
+It feels like my chest _does_ have a heart. You make my heart beat. Your smile brings a smile to my face, your pain brings pain to my heart.
+
+I don’t show my emotions, but I think this man behind the mask is falling for you.”
+
+当阅读到这里时，你会问蝙蝠侠：“等等，这是给谁的？”蝙蝠侠说：
+
+“这是给超人的。”
+
+
+
+你说：哦！我还以为是给神奇女侠的呢。
+
+蝙蝠侠说：不，这是给超人的，请在最后写上 “I love you Superman.”。
+
+好的，我们来写：
+
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+```
+
+这封信差不多完成了，蝙蝠侠另外想再做两次改变。蝙蝠侠希望在最后段落的第一句中的 “does” 一词是斜体，而 “I love you Superman” 这句话是粗体的。
+
+我们使用 `` 和 `` 以斜体和粗体显示文本。让我们来更新这些更改：
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+```
+
+
+
+### HTML 中的样式
+
+你可以通过三种方式设置样式或定义 HTML 元素的外观：
+
+* 内联样式：我们使用元素的 `style` 属性来编写样式。这是我们迄今为止使用的，但这不是一个好的实践。
+* 嵌入式样式：我们在由 `` 包裹的 “style” 元素中编写所有样式。
+* 链接样式表：我们在具有 .css 扩展名的单独文件中编写所有元素的样式。此文件称为样式表。
+
+让我们来看看如何定义 `` 的内联样式：
+
+```
+
+```
+
+我们可以在 `` 里面写同样的样式：
+
+```
+div{
+ width:550px;
+}
+```
+
+在嵌入式样式中，我们编写的样式是与元素分开的。所以我们需要一种方法来关联元素及其样式。第一个单词 “div” 就做了这样的活。它让浏览器知道花括号 `{...}` 里面的所有样式都属于 “div” 元素。由于这种语法确定要应用样式的元素，因此它称为一个选择器。
+
+我们编写样式的方式保持不变：属性（`width`）和值（`550px`）用冒号（`:`）分隔，以分号（`;`）结束。
+
+让我们从 `` 和 `![]()
` 元素中删除内联样式，将其写入 `
+```
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+```
+
+保存并刷新，结果应保持不变。
+
+但是有一个大问题，如果我们的 HTML 文件中有多个 `` 和 `![]()
` 元素该怎么办？这样我们在 `
+```
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+```
+
+HTML 已经准备好了嵌入式样式。
+
+但是，你可以看到，随着我们包含越来越多的样式，`` 将变得很大。这可能很快会混乱我们的主 HTML 文件。
+
+因此，让我们更进一步，通过将 ``。
+
+我们需要使用 HTML 文件中的 `` 标签来将新创建的 CSS 文件链接到 HTML 文件。以下是我们如何做到这一点：
+
+```
+
+```
+
+我们使用 `` 元素在 HTML 文档中包含外部资源，它主要用于链接样式表。我们使用的三个属性是：
+
+* `rel`：关系。链接文件与文档的关系。具有 .css 扩展名的文件称为样式表，因此我们保留 rel=“stylesheet”。
+* `type`：链接文件的类型；对于一个 CSS 文件来说它是 “text/css”。
+* `href`：超文本参考。链接文件的位置。
+
+link 元素的结尾没有 ``。因此，`` 也是一个自闭合的标签。
+
+```
+
+```
+
+如果只是得到一个女朋友，那么很容易：D
+
+可惜没有那么简单，让我们继续前进。
+
+这是我们 “loveletter.html” 的内容：
+
+```
+
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+```
+
+“style.css” 内容：
+
+```
+#letter-container{
+ width:550px;
+}
+#header-bat-logo{
+ width:100%;
+}
+```
+
+保存文件并刷新，浏览器中的输出应保持不变。
+
+### 一些手续
+
+我们的情书已经准备好给蝙蝠侠，但还有一些正式的片段。
+
+与其他任何编程语言一样，HTML 自出生以来（1990 年）经历过许多版本，当前版本是 HTML5。
+
+那么，浏览器如何知道你使用哪个版本的 HTML 来编写页面呢？要告诉浏览器你正在使用 HTML5，你需要在页面顶部包含 ``。对于旧版本的 HTML，这行不同，但你不需要了解它们，因为我们不再使用它们了。
+
+此外，在之前的 HTML 版本中，我们曾经将整个文档封装在 `` 标签内。整个文件分为两个主要部分：头部在 `` 里面，主体在 `` 里面。这在 HTML5 中不是必须的，但由于兼容性原因，我们仍然这样做。让我们用 ``, ``、 `` 和 `` 更新我们的代码：
+
+```
+
+
+
+
+
+
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+
+
+```
+
+主要内容在 `` 里面，元信息在 `` 里面。所以我们把 `` 保存在 `` 里面并加载 `` 里面的样式表。
+
+保存并刷新，你的 HTML 页面应显示与之前相同的内容。
+
+### HTML 的标题
+
+我发誓，这是最后一次改变。
+
+你可能已经注意到选项卡的标题正在显示 HTML 文件的路径：
+
+
+
+我们可以使用 `` 标签来定义 HTML 文件的标题。标题标签也像链接标签一样在 `<head>` 内部。让我们我们在标题中加上 “Bat Letter”：
+
+```
+<!DOCTYPE html>
+<html>
+<head>
+ <title>Bat Letter
+
+
+
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+
+
+```
+
+保存并刷新，你将看到在选项卡上显示的是 “Bat Letter” 而不是文件路径。
+
+蝙蝠侠的情书现在已经完成。
+
+恭喜！你用 HTML 制作了蝙蝠侠的情书。
+
+
+
+### 我们学到了什么
+
+我们学习了以下新概念：
+
+ * 一个 HTML 文档的结构
+ * 在 HTML 中如何写元素（``）
+ * 如何使用 style 属性在元素内编写样式（这称为内联样式，尽可能避免这种情况）
+ * 如何在 `` 中编写元素的样式（这称为嵌入式样式）
+ * 在 HTML 中如何使用 `` 在单独的文件中编写样式并链接它（这称为链接样式表）
+ * 什么是标签名称，属性，开始标签和结束标签
+ * 如何使用 id 属性为一个元素赋予 id
+ * CSS 中的标签选择器和 id 选择器
+
+我们学习了以下 HTML 标签：
+
+ * ``：用于段落
+ * `
`：用于换行
+ * `
`、`
` 和 `` 标签来添加标题，`` 是最大的标题和最主要的标题，`` 是最小的标题。
+
+
+
+让我们在第二段之前使用 `` 做主标题和一个副标题：
+
+```
+
+ Bat Letter
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+
+```
+
+保存，刷新。
+
+
+
+### HTML 中的图像
+
+我们的情书尚未完成，但在继续之前，缺少一件大事：蝙蝠侠标志。你见过是蝙蝠侠的东西但没有蝙蝠侠的标志吗？
+
+并没有。
+
+所以，让我们在情书中添加一个蝙蝠侠标志。
+
+在 HTML 中包含图像就像在一个 Word 文件中包含图像一样。在 MS Word 中，你到 “菜单 -> 插入 -> 图像 -> 然后导航到图像位置为止 -> 选择图像 -> 单击插入”。
+
+在 HTML 中，我们使用 `![]()
` 标签让浏览器知道我们需要加载的图像，而不是单击菜单。我们在 `src` 属性中写入文件的位置和名称。如果图像在项目根目录中，我们可以简单地在 `src` 属性中写入图像文件的名称。
+
+在我们深入编码之前，从[这里][3]下载蝙蝠侠标志。你可能希望裁剪图像中的额外空白区域。复制项目根目录中的图像并将其重命名为 “bat-logo.jpeg”。
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+
+```
+
+我们在第 3 行包含了 `![]()
` 标签。这个标签也是一个自闭合的标签，所以我们不需要写 ``。在 `src` 属性中，我们给出了图像文件的名称。这个名称应与图像名称完全相同，包括扩展名（.jpeg）及其大小写。
+
+保存并刷新，查看结果。
+
+
+
+该死的！刚刚发生了什么？
+
+当使用 `![]()
` 标签包含图像时，默认情况下，图像将以其原始分辨率显示。在我们的例子中，图像比 550px 宽得多。让我们使用 `style` 属性定义它的宽度：
+
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+
+```
+
+你会注意到，这次我们定义宽度使用了 “%” 而不是 “px”。当我们在 “%” 中定义宽度时，它将占据父元素宽度的百分比。因此，100% 的 550px 将为我们提供 550px。
+
+保存并刷新，查看结果。
+
+
+
+太棒了！这让蝙蝠侠的脸露出了羞涩的微笑 :)。
+
+### HTML 中的粗体和斜体
+
+现在蝙蝠侠想在最后几段中承认他的爱。他有以下文本供你用 HTML 编写：
+
+“I have a confession to make
+
+It feels like my chest _does_ have a heart. You make my heart beat. Your smile brings a smile to my face, your pain brings pain to my heart.
+
+I don’t show my emotions, but I think this man behind the mask is falling for you.”
+
+当阅读到这里时，你会问蝙蝠侠：“等等，这是给谁的？”蝙蝠侠说：
+
+“这是给超人的。”
+
+
+
+你说：哦！我还以为是给神奇女侠的呢。
+
+蝙蝠侠说：不，这是给超人的，请在最后写上 “I love you Superman.”。
+
+好的，我们来写：
+
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+```
+
+这封信差不多完成了，蝙蝠侠另外想再做两次改变。蝙蝠侠希望在最后段落的第一句中的 “does” 一词是斜体，而 “I love you Superman” 这句话是粗体的。
+
+我们使用 `` 和 `` 以斜体和粗体显示文本。让我们来更新这些更改：
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+```
+
+
+
+### HTML 中的样式
+
+你可以通过三种方式设置样式或定义 HTML 元素的外观：
+
+* 内联样式：我们使用元素的 `style` 属性来编写样式。这是我们迄今为止使用的，但这不是一个好的实践。
+* 嵌入式样式：我们在由 `` 包裹的 “style” 元素中编写所有样式。
+* 链接样式表：我们在具有 .css 扩展名的单独文件中编写所有元素的样式。此文件称为样式表。
+
+让我们来看看如何定义 `` 的内联样式：
+
+```
+
+```
+
+我们可以在 `` 里面写同样的样式：
+
+```
+div{
+ width:550px;
+}
+```
+
+在嵌入式样式中，我们编写的样式是与元素分开的。所以我们需要一种方法来关联元素及其样式。第一个单词 “div” 就做了这样的活。它让浏览器知道花括号 `{...}` 里面的所有样式都属于 “div” 元素。由于这种语法确定要应用样式的元素，因此它称为一个选择器。
+
+我们编写样式的方式保持不变：属性（`width`）和值（`550px`）用冒号（`:`）分隔，以分号（`;`）结束。
+
+让我们从 `` 和 `![]()
` 元素中删除内联样式，将其写入 `
+```
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+```
+
+保存并刷新，结果应保持不变。
+
+但是有一个大问题，如果我们的 HTML 文件中有多个 `` 和 `![]()
` 元素该怎么办？这样我们在 `
+```
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+```
+
+HTML 已经准备好了嵌入式样式。
+
+但是，你可以看到，随着我们包含越来越多的样式，`` 将变得很大。这可能很快会混乱我们的主 HTML 文件。
+
+因此，让我们更进一步，通过将 ``。
+
+我们需要使用 HTML 文件中的 `` 标签来将新创建的 CSS 文件链接到 HTML 文件。以下是我们如何做到这一点：
+
+```
+
+```
+
+我们使用 `` 元素在 HTML 文档中包含外部资源，它主要用于链接样式表。我们使用的三个属性是：
+
+* `rel`：关系。链接文件与文档的关系。具有 .css 扩展名的文件称为样式表，因此我们保留 rel=“stylesheet”。
+* `type`：链接文件的类型；对于一个 CSS 文件来说它是 “text/css”。
+* `href`：超文本参考。链接文件的位置。
+
+link 元素的结尾没有 ``。因此，`` 也是一个自闭合的标签。
+
+```
+
+```
+
+如果只是得到一个女朋友，那么很容易：D
+
+可惜没有那么简单，让我们继续前进。
+
+这是我们 “loveletter.html” 的内容：
+
+```
+
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+```
+
+“style.css” 内容：
+
+```
+#letter-container{
+ width:550px;
+}
+#header-bat-logo{
+ width:100%;
+}
+```
+
+保存文件并刷新，浏览器中的输出应保持不变。
+
+### 一些手续
+
+我们的情书已经准备好给蝙蝠侠，但还有一些正式的片段。
+
+与其他任何编程语言一样，HTML 自出生以来（1990 年）经历过许多版本，当前版本是 HTML5。
+
+那么，浏览器如何知道你使用哪个版本的 HTML 来编写页面呢？要告诉浏览器你正在使用 HTML5，你需要在页面顶部包含 ``。对于旧版本的 HTML，这行不同，但你不需要了解它们，因为我们不再使用它们了。
+
+此外，在之前的 HTML 版本中，我们曾经将整个文档封装在 `` 标签内。整个文件分为两个主要部分：头部在 `` 里面，主体在 `` 里面。这在 HTML5 中不是必须的，但由于兼容性原因，我们仍然这样做。让我们用 ``, ``、 `` 和 `` 更新我们的代码：
+
+```
+
+
+
+
+
+
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+
+
+```
+
+主要内容在 `` 里面，元信息在 `` 里面。所以我们把 `` 保存在 `` 里面并加载 `` 里面的样式表。
+
+保存并刷新，你的 HTML 页面应显示与之前相同的内容。
+
+### HTML 的标题
+
+我发誓，这是最后一次改变。
+
+你可能已经注意到选项卡的标题正在显示 HTML 文件的路径：
+
+
+
+我们可以使用 `` 标签来定义 HTML 文件的标题。标题标签也像链接标签一样在 `<head>` 内部。让我们我们在标题中加上 “Bat Letter”：
+
+```
+<!DOCTYPE html>
+<html>
+<head>
+ <title>Bat Letter
+
+
+
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+
+
+```
+
+保存并刷新，你将看到在选项卡上显示的是 “Bat Letter” 而不是文件路径。
+
+蝙蝠侠的情书现在已经完成。
+
+恭喜！你用 HTML 制作了蝙蝠侠的情书。
+
+
+
+### 我们学到了什么
+
+我们学习了以下新概念：
+
+ * 一个 HTML 文档的结构
+ * 在 HTML 中如何写元素（``）
+ * 如何使用 style 属性在元素内编写样式（这称为内联样式，尽可能避免这种情况）
+ * 如何在 `` 中编写元素的样式（这称为嵌入式样式）
+ * 在 HTML 中如何使用 `` 在单独的文件中编写样式并链接它（这称为链接样式表）
+ * 什么是标签名称，属性，开始标签和结束标签
+ * 如何使用 id 属性为一个元素赋予 id
+ * CSS 中的标签选择器和 id 选择器
+
+我们学习了以下 HTML 标签：
+
+ * ``：用于段落
+ * `
`：用于换行
+ * `
`、`
` 是最大的标题和最主要的标题，`` 是最小的标题。
+
+
+
+让我们在第二段之前使用 `` 做主标题和一个副标题：
+
+```
+
+ Bat Letter
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+
+```
+
+保存，刷新。
+
+
+
+### HTML 中的图像
+
+我们的情书尚未完成，但在继续之前，缺少一件大事：蝙蝠侠标志。你见过是蝙蝠侠的东西但没有蝙蝠侠的标志吗？
+
+并没有。
+
+所以，让我们在情书中添加一个蝙蝠侠标志。
+
+在 HTML 中包含图像就像在一个 Word 文件中包含图像一样。在 MS Word 中，你到 “菜单 -> 插入 -> 图像 -> 然后导航到图像位置为止 -> 选择图像 -> 单击插入”。
+
+在 HTML 中，我们使用 `![]()
` 标签让浏览器知道我们需要加载的图像，而不是单击菜单。我们在 `src` 属性中写入文件的位置和名称。如果图像在项目根目录中，我们可以简单地在 `src` 属性中写入图像文件的名称。
+
+在我们深入编码之前，从[这里][3]下载蝙蝠侠标志。你可能希望裁剪图像中的额外空白区域。复制项目根目录中的图像并将其重命名为 “bat-logo.jpeg”。
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+
+```
+
+我们在第 3 行包含了 `![]()
` 标签。这个标签也是一个自闭合的标签，所以我们不需要写 ``。在 `src` 属性中，我们给出了图像文件的名称。这个名称应与图像名称完全相同，包括扩展名（.jpeg）及其大小写。
+
+保存并刷新，查看结果。
+
+
+
+该死的！刚刚发生了什么？
+
+当使用 `![]()
` 标签包含图像时，默认情况下，图像将以其原始分辨率显示。在我们的例子中，图像比 550px 宽得多。让我们使用 `style` 属性定义它的宽度：
+
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+
+```
+
+你会注意到，这次我们定义宽度使用了 “%” 而不是 “px”。当我们在 “%” 中定义宽度时，它将占据父元素宽度的百分比。因此，100% 的 550px 将为我们提供 550px。
+
+保存并刷新，查看结果。
+
+
+
+太棒了！这让蝙蝠侠的脸露出了羞涩的微笑 :)。
+
+### HTML 中的粗体和斜体
+
+现在蝙蝠侠想在最后几段中承认他的爱。他有以下文本供你用 HTML 编写：
+
+“I have a confession to make
+
+It feels like my chest _does_ have a heart. You make my heart beat. Your smile brings a smile to my face, your pain brings pain to my heart.
+
+I don’t show my emotions, but I think this man behind the mask is falling for you.”
+
+当阅读到这里时，你会问蝙蝠侠：“等等，这是给谁的？”蝙蝠侠说：
+
+“这是给超人的。”
+
+
+
+你说：哦！我还以为是给神奇女侠的呢。
+
+蝙蝠侠说：不，这是给超人的，请在最后写上 “I love you Superman.”。
+
+好的，我们来写：
+
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+```
+
+这封信差不多完成了，蝙蝠侠另外想再做两次改变。蝙蝠侠希望在最后段落的第一句中的 “does” 一词是斜体，而 “I love you Superman” 这句话是粗体的。
+
+我们使用 `` 和 `` 以斜体和粗体显示文本。让我们来更新这些更改：
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+```
+
+
+
+### HTML 中的样式
+
+你可以通过三种方式设置样式或定义 HTML 元素的外观：
+
+* 内联样式：我们使用元素的 `style` 属性来编写样式。这是我们迄今为止使用的，但这不是一个好的实践。
+* 嵌入式样式：我们在由 `` 包裹的 “style” 元素中编写所有样式。
+* 链接样式表：我们在具有 .css 扩展名的单独文件中编写所有元素的样式。此文件称为样式表。
+
+让我们来看看如何定义 `` 的内联样式：
+
+```
+
+```
+
+我们可以在 `` 里面写同样的样式：
+
+```
+div{
+ width:550px;
+}
+```
+
+在嵌入式样式中，我们编写的样式是与元素分开的。所以我们需要一种方法来关联元素及其样式。第一个单词 “div” 就做了这样的活。它让浏览器知道花括号 `{...}` 里面的所有样式都属于 “div” 元素。由于这种语法确定要应用样式的元素，因此它称为一个选择器。
+
+我们编写样式的方式保持不变：属性（`width`）和值（`550px`）用冒号（`:`）分隔，以分号（`;`）结束。
+
+让我们从 `` 和 `![]()
` 元素中删除内联样式，将其写入 `
+```
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+```
+
+保存并刷新，结果应保持不变。
+
+但是有一个大问题，如果我们的 HTML 文件中有多个 `` 和 `![]()
` 元素该怎么办？这样我们在 `
+```
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+```
+
+HTML 已经准备好了嵌入式样式。
+
+但是，你可以看到，随着我们包含越来越多的样式，`` 将变得很大。这可能很快会混乱我们的主 HTML 文件。
+
+因此，让我们更进一步，通过将 ``。
+
+我们需要使用 HTML 文件中的 `` 标签来将新创建的 CSS 文件链接到 HTML 文件。以下是我们如何做到这一点：
+
+```
+
+```
+
+我们使用 `` 元素在 HTML 文档中包含外部资源，它主要用于链接样式表。我们使用的三个属性是：
+
+* `rel`：关系。链接文件与文档的关系。具有 .css 扩展名的文件称为样式表，因此我们保留 rel=“stylesheet”。
+* `type`：链接文件的类型；对于一个 CSS 文件来说它是 “text/css”。
+* `href`：超文本参考。链接文件的位置。
+
+link 元素的结尾没有 ``。因此，`` 也是一个自闭合的标签。
+
+```
+
+```
+
+如果只是得到一个女朋友，那么很容易：D
+
+可惜没有那么简单，让我们继续前进。
+
+这是我们 “loveletter.html” 的内容：
+
+```
+
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+```
+
+“style.css” 内容：
+
+```
+#letter-container{
+ width:550px;
+}
+#header-bat-logo{
+ width:100%;
+}
+```
+
+保存文件并刷新，浏览器中的输出应保持不变。
+
+### 一些手续
+
+我们的情书已经准备好给蝙蝠侠，但还有一些正式的片段。
+
+与其他任何编程语言一样，HTML 自出生以来（1990 年）经历过许多版本，当前版本是 HTML5。
+
+那么，浏览器如何知道你使用哪个版本的 HTML 来编写页面呢？要告诉浏览器你正在使用 HTML5，你需要在页面顶部包含 ``。对于旧版本的 HTML，这行不同，但你不需要了解它们，因为我们不再使用它们了。
+
+此外，在之前的 HTML 版本中，我们曾经将整个文档封装在 `` 标签内。整个文件分为两个主要部分：头部在 `` 里面，主体在 `` 里面。这在 HTML5 中不是必须的，但由于兼容性原因，我们仍然这样做。让我们用 ``, ``、 `` 和 `` 更新我们的代码：
+
+```
+
+
+
+
+
+
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+
+
+```
+
+主要内容在 `` 里面，元信息在 `` 里面。所以我们把 `` 保存在 `` 里面并加载 `` 里面的样式表。
+
+保存并刷新，你的 HTML 页面应显示与之前相同的内容。
+
+### HTML 的标题
+
+我发誓，这是最后一次改变。
+
+你可能已经注意到选项卡的标题正在显示 HTML 文件的路径：
+
+
+
+我们可以使用 `` 标签来定义 HTML 文件的标题。标题标签也像链接标签一样在 `<head>` 内部。让我们我们在标题中加上 “Bat Letter”：
+
+```
+<!DOCTYPE html>
+<html>
+<head>
+ <title>Bat Letter
+
+
+
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+
+
+```
+
+保存并刷新，你将看到在选项卡上显示的是 “Bat Letter” 而不是文件路径。
+
+蝙蝠侠的情书现在已经完成。
+
+恭喜！你用 HTML 制作了蝙蝠侠的情书。
+
+
+
+### 我们学到了什么
+
+我们学习了以下新概念：
+
+ * 一个 HTML 文档的结构
+ * 在 HTML 中如何写元素（``）
+ * 如何使用 style 属性在元素内编写样式（这称为内联样式，尽可能避免这种情况）
+ * 如何在 `` 中编写元素的样式（这称为嵌入式样式）
+ * 在 HTML 中如何使用 `` 在单独的文件中编写样式并链接它（这称为链接样式表）
+ * 什么是标签名称，属性，开始标签和结束标签
+ * 如何使用 id 属性为一个元素赋予 id
+ * CSS 中的标签选择器和 id 选择器
+
+我们学习了以下 HTML 标签：
+
+ * ``：用于段落
+ * `
`：用于换行
+ * `
`、`
` 做主标题和一个副标题：
+
+```
+
+ Bat Letter
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+
+```
+
+保存，刷新。
+
+
+
+### HTML 中的图像
+
+我们的情书尚未完成，但在继续之前，缺少一件大事：蝙蝠侠标志。你见过是蝙蝠侠的东西但没有蝙蝠侠的标志吗？
+
+并没有。
+
+所以，让我们在情书中添加一个蝙蝠侠标志。
+
+在 HTML 中包含图像就像在一个 Word 文件中包含图像一样。在 MS Word 中，你到 “菜单 -> 插入 -> 图像 -> 然后导航到图像位置为止 -> 选择图像 -> 单击插入”。
+
+在 HTML 中，我们使用 `![]()
` 标签让浏览器知道我们需要加载的图像，而不是单击菜单。我们在 `src` 属性中写入文件的位置和名称。如果图像在项目根目录中，我们可以简单地在 `src` 属性中写入图像文件的名称。
+
+在我们深入编码之前，从[这里][3]下载蝙蝠侠标志。你可能希望裁剪图像中的额外空白区域。复制项目根目录中的图像并将其重命名为 “bat-logo.jpeg”。
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+
+```
+
+我们在第 3 行包含了 `![]()
` 标签。这个标签也是一个自闭合的标签，所以我们不需要写 ``。在 `src` 属性中，我们给出了图像文件的名称。这个名称应与图像名称完全相同，包括扩展名（.jpeg）及其大小写。
+
+保存并刷新，查看结果。
+
+
+
+该死的！刚刚发生了什么？
+
+当使用 `![]()
` 标签包含图像时，默认情况下，图像将以其原始分辨率显示。在我们的例子中，图像比 550px 宽得多。让我们使用 `style` 属性定义它的宽度：
+
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+
+```
+
+你会注意到，这次我们定义宽度使用了 “%” 而不是 “px”。当我们在 “%” 中定义宽度时，它将占据父元素宽度的百分比。因此，100% 的 550px 将为我们提供 550px。
+
+保存并刷新，查看结果。
+
+
+
+太棒了！这让蝙蝠侠的脸露出了羞涩的微笑 :)。
+
+### HTML 中的粗体和斜体
+
+现在蝙蝠侠想在最后几段中承认他的爱。他有以下文本供你用 HTML 编写：
+
+“I have a confession to make
+
+It feels like my chest _does_ have a heart. You make my heart beat. Your smile brings a smile to my face, your pain brings pain to my heart.
+
+I don’t show my emotions, but I think this man behind the mask is falling for you.”
+
+当阅读到这里时，你会问蝙蝠侠：“等等，这是给谁的？”蝙蝠侠说：
+
+“这是给超人的。”
+
+
+
+你说：哦！我还以为是给神奇女侠的呢。
+
+蝙蝠侠说：不，这是给超人的，请在最后写上 “I love you Superman.”。
+
+好的，我们来写：
+
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+```
+
+这封信差不多完成了，蝙蝠侠另外想再做两次改变。蝙蝠侠希望在最后段落的第一句中的 “does” 一词是斜体，而 “I love you Superman” 这句话是粗体的。
+
+我们使用 `` 和 `` 以斜体和粗体显示文本。让我们来更新这些更改：
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+```
+
+
+
+### HTML 中的样式
+
+你可以通过三种方式设置样式或定义 HTML 元素的外观：
+
+* 内联样式：我们使用元素的 `style` 属性来编写样式。这是我们迄今为止使用的，但这不是一个好的实践。
+* 嵌入式样式：我们在由 `` 包裹的 “style” 元素中编写所有样式。
+* 链接样式表：我们在具有 .css 扩展名的单独文件中编写所有元素的样式。此文件称为样式表。
+
+让我们来看看如何定义 `` 的内联样式：
+
+```
+
+```
+
+我们可以在 `` 里面写同样的样式：
+
+```
+div{
+ width:550px;
+}
+```
+
+在嵌入式样式中，我们编写的样式是与元素分开的。所以我们需要一种方法来关联元素及其样式。第一个单词 “div” 就做了这样的活。它让浏览器知道花括号 `{...}` 里面的所有样式都属于 “div” 元素。由于这种语法确定要应用样式的元素，因此它称为一个选择器。
+
+我们编写样式的方式保持不变：属性（`width`）和值（`550px`）用冒号（`:`）分隔，以分号（`;`）结束。
+
+让我们从 `` 和 `![]()
` 元素中删除内联样式，将其写入 `
+```
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+```
+
+保存并刷新，结果应保持不变。
+
+但是有一个大问题，如果我们的 HTML 文件中有多个 `` 和 `![]()
` 元素该怎么办？这样我们在 `
+```
+
+```
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+```
+
+```
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+```
+
+HTML 已经准备好了嵌入式样式。
+
+但是，你可以看到，随着我们包含越来越多的样式，`` 将变得很大。这可能很快会混乱我们的主 HTML 文件。
+
+因此，让我们更进一步，通过将 ``。
+
+我们需要使用 HTML 文件中的 `` 标签来将新创建的 CSS 文件链接到 HTML 文件。以下是我们如何做到这一点：
+
+```
+
+```
+
+我们使用 `` 元素在 HTML 文档中包含外部资源，它主要用于链接样式表。我们使用的三个属性是：
+
+* `rel`：关系。链接文件与文档的关系。具有 .css 扩展名的文件称为样式表，因此我们保留 rel=“stylesheet”。
+* `type`：链接文件的类型；对于一个 CSS 文件来说它是 “text/css”。
+* `href`：超文本参考。链接文件的位置。
+
+link 元素的结尾没有 ``。因此，`` 也是一个自闭合的标签。
+
+```
+
+```
+
+如果只是得到一个女朋友，那么很容易：D
+
+可惜没有那么简单，让我们继续前进。
+
+这是我们 “loveletter.html” 的内容：
+
+```
+
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+```
+
+“style.css” 内容：
+
+```
+#letter-container{
+ width:550px;
+}
+#header-bat-logo{
+ width:100%;
+}
+```
+
+保存文件并刷新，浏览器中的输出应保持不变。
+
+### 一些手续
+
+我们的情书已经准备好给蝙蝠侠，但还有一些正式的片段。
+
+与其他任何编程语言一样，HTML 自出生以来（1990 年）经历过许多版本，当前版本是 HTML5。
+
+那么，浏览器如何知道你使用哪个版本的 HTML 来编写页面呢？要告诉浏览器你正在使用 HTML5，你需要在页面顶部包含 ``。对于旧版本的 HTML，这行不同，但你不需要了解它们，因为我们不再使用它们了。
+
+此外，在之前的 HTML 版本中，我们曾经将整个文档封装在 `` 标签内。整个文件分为两个主要部分：头部在 `` 里面，主体在 `` 里面。这在 HTML5 中不是必须的，但由于兼容性原因，我们仍然这样做。让我们用 ``, ``、 `` 和 `` 更新我们的代码：
+
+```
+
+
+
+
+
+
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+
+
+```
+
+主要内容在 `` 里面，元信息在 `` 里面。所以我们把 `` 保存在 `` 里面并加载 `` 里面的样式表。
+
+保存并刷新，你的 HTML 页面应显示与之前相同的内容。
+
+### HTML 的标题
+
+我发誓，这是最后一次改变。
+
+你可能已经注意到选项卡的标题正在显示 HTML 文件的路径：
+
+
+
+我们可以使用 `` 标签来定义 HTML 文件的标题。标题标签也像链接标签一样在 `<head>` 内部。让我们我们在标题中加上 “Bat Letter”：
+
+```
+<!DOCTYPE html>
+<html>
+<head>
+ <title>Bat Letter
+
+
+
+
+ Bat Letter
+
+
+ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
+
+ You are the light of my life
+
+ You complete my darkness with your light. I love:
+
+
+
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time.
+
+ I have a confession to make
+
+ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
+
+
+ I don't show my emotions, but I think this man behind the mask is falling for you.
+
+ I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+
+
+```
+
+保存并刷新，你将看到在选项卡上显示的是 “Bat Letter” 而不是文件路径。
+
+蝙蝠侠的情书现在已经完成。
+
+恭喜！你用 HTML 制作了蝙蝠侠的情书。
+
+
+
+### 我们学到了什么
+
+我们学习了以下新概念：
+
+ * 一个 HTML 文档的结构
+ * 在 HTML 中如何写元素（``）
+ * 如何使用 style 属性在元素内编写样式（这称为内联样式，尽可能避免这种情况）
+ * 如何在 `` 中编写元素的样式（这称为嵌入式样式）
+ * 在 HTML 中如何使用 `` 在单独的文件中编写样式并链接它（这称为链接样式表）
+ * 什么是标签名称，属性，开始标签和结束标签
+ * 如何使用 id 属性为一个元素赋予 id
+ * CSS 中的标签选择器和 id 选择器
+
+我们学习了以下 HTML 标签：
+
+ * ``：用于段落
+ * `
`：用于换行
+ * `
`、`
Bat Letter
++ After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you. +
+``` + +``` +You are the light of my life
++ You complete my darkness with your light. I love: +
+-
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time. +
+Bat Letter
+
+ + After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you. +
+``` + +``` +You are the light of my life
++ You complete my darkness with your light. I love: +
+-
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time. +
+Bat Letter
+
+ + After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you. +
+``` + +``` +You are the light of my life
++ You complete my darkness with your light. I love: +
+-
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time. +
+Bat Letter
+
+ + After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you. +
+``` + +``` +You are the light of my life
++ You complete my darkness with your light. I love: +
+-
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time. +
+I have a confession to make
++ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart. +
++ I don't show my emotions, but I think this man behind the mask is falling for you. +
+I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
Bat Letter
+
+ + After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you. +
+``` + +``` +You are the light of my life
++ You complete my darkness with your light. I love: +
+-
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time. +
+I have a confession to make
++ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart. +
++ I don't show my emotions, but I think this man behind the mask is falling for you. +
+I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+```
+
+我们可以在 `` 里面写同样的样式：
+
+```
+div{
+ width:550px;
+}
+```
+
+在嵌入式样式中，我们编写的样式是与元素分开的。所以我们需要一种方法来关联元素及其样式。第一个单词 “div” 就做了这样的活。它让浏览器知道花括号 `{...}` 里面的所有样式都属于 “div” 元素。由于这种语法确定要应用样式的元素，因此它称为一个选择器。
+
+我们编写样式的方式保持不变：属性（`width`）和值（`550px`）用冒号（`:`）分隔，以分号（`;`）结束。
+
+让我们从 `
` 和 `![]()
` 元素中删除内联样式，将其写入 `
+```
+
+```
+
+
+
+```
+
+保存并刷新，结果应保持不变。
+
+但是有一个大问题，如果我们的 HTML 文件中有多个 `Bat Letter
+
+ + After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you. +
+``` + +``` +You are the light of my life
++ You complete my darkness with your light. I love: +
+-
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time. +
+I have a confession to make
++ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart. +
++ I don't show my emotions, but I think this man behind the mask is falling for you. +
+I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
` 和 `![]()
` 元素该怎么办？这样我们在 `
+```
+
+```
+`, ``、 `` 和 `` 更新我们的代码：
+
+```
+
+
+
+
+
+
+
+
+
+```
+
+HTML 已经准备好了嵌入式样式。
+
+但是，你可以看到，随着我们包含越来越多的样式，`` 将变得很大。这可能很快会混乱我们的主 HTML 文件。
+
+因此，让我们更进一步，通过将 ``。
+
+我们需要使用 HTML 文件中的 `` 标签来将新创建的 CSS 文件链接到 HTML 文件。以下是我们如何做到这一点：
+
+```
+
+```
+
+我们使用 `` 元素在 HTML 文档中包含外部资源，它主要用于链接样式表。我们使用的三个属性是：
+
+* `rel`：关系。链接文件与文档的关系。具有 .css 扩展名的文件称为样式表，因此我们保留 rel=“stylesheet”。
+* `type`：链接文件的类型；对于一个 CSS 文件来说它是 “text/css”。
+* `href`：超文本参考。链接文件的位置。
+
+link 元素的结尾没有 ``。因此，`` 也是一个自闭合的标签。
+
+```
+
+```
+
+如果只是得到一个女朋友，那么很容易：D
+
+可惜没有那么简单，让我们继续前进。
+
+这是我们 “loveletter.html” 的内容：
+
+```
+
+Bat Letter
+
+ + After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you. +
+``` + +``` +You are the light of my life
++ You complete my darkness with your light. I love: +
+-
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time. +
+I have a confession to make
++ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart. +
++ I don't show my emotions, but I think this man behind the mask is falling for you. +
+I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+
+```
+
+“style.css” 内容：
+
+```
+#letter-container{
+ width:550px;
+}
+#header-bat-logo{
+ width:100%;
+}
+```
+
+保存文件并刷新，浏览器中的输出应保持不变。
+
+### 一些手续
+
+我们的情书已经准备好给蝙蝠侠，但还有一些正式的片段。
+
+与其他任何编程语言一样，HTML 自出生以来（1990 年）经历过许多版本，当前版本是 HTML5。
+
+那么，浏览器如何知道你使用哪个版本的 HTML 来编写页面呢？要告诉浏览器你正在使用 HTML5，你需要在页面顶部包含 ``。对于旧版本的 HTML，这行不同，但你不需要了解它们，因为我们不再使用它们了。
+
+此外，在之前的 HTML 版本中，我们曾经将整个文档封装在 `` 标签内。整个文件分为两个主要部分：头部在 `` 里面，主体在 `` 里面。这在 HTML5 中不是必须的，但由于兼容性原因，我们仍然这样做。让我们用 `Bat Letter
+
+ + After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you. +
+You are the light of my life
++ You complete my darkness with your light. I love: +
+-
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time. +
+I have a confession to make
++ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart. +
++ I don't show my emotions, but I think this man behind the mask is falling for you. +
+I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
+
+
+
+
+```
+
+主要内容在 `` 里面，元信息在 `` 里面。所以我们把 `Bat Letter
+
+ + After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you. +
+You are the light of my life
++ You complete my darkness with your light. I love: +
+-
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time. +
+I have a confession to make
++ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart. +
++ I don't show my emotions, but I think this man behind the mask is falling for you. +
+I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
` 保存在 `` 里面并加载 `` 里面的样式表。
+
+保存并刷新，你的 HTML 页面应显示与之前相同的内容。
+
+### HTML 的标题
+
+我发誓，这是最后一次改变。
+
+你可能已经注意到选项卡的标题正在显示 HTML 文件的路径：
+
+
+
+我们可以使用 `` 标签来定义 HTML 文件的标题。标题标签也像链接标签一样在 `<head>` 内部。让我们我们在标题中加上 “Bat Letter”：
+
+```
+<!DOCTYPE html>
+<html>
+<head>
+ <title>Bat Letter
+
+
+
+
+
+
+
+
+```
+
+保存并刷新，你将看到在选项卡上显示的是 “Bat Letter” 而不是文件路径。
+
+蝙蝠侠的情书现在已经完成。
+
+恭喜！你用 HTML 制作了蝙蝠侠的情书。
+
+
+
+### 我们学到了什么
+
+我们学习了以下新概念：
+
+ * 一个 HTML 文档的结构
+ * 在 HTML 中如何写元素（``）
+ * 如何使用 style 属性在元素内编写样式（这称为内联样式，尽可能避免这种情况）
+ * 如何在 `` 中编写元素的样式（这称为嵌入式样式）
+ * 在 HTML 中如何使用 `` 在单独的文件中编写样式并链接它（这称为链接样式表）
+ * 什么是标签名称，属性，开始标签和结束标签
+ * 如何使用 id 属性为一个元素赋予 id
+ * CSS 中的标签选择器和 id 选择器
+
+我们学习了以下 HTML 标签：
+
+ * `Bat Letter
+
+ + After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you. +
+You are the light of my life
++ You complete my darkness with your light. I love: +
+-
+
+ I have learned a lot from you. You have occupied a special place in my heart over the time. +
+I have a confession to make
++ It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart. +
++ I don't show my emotions, but I think this man behind the mask is falling for you. +
+I love you Superman.
+
+ Your not-so-secret-lover,
+ Batman
+
`：用于段落
+ * `
`：用于换行
+ * `
- `、`