From 06dffa98feafd305ca1bc18e3b99e57d86ac830d Mon Sep 17 00:00:00 2001 From: geekpi Date: Wed, 22 Sep 2021 08:43:59 +0800 Subject: [PATCH] translating --- ... and tasks with the Linux watch command.md | 124 ------------------ ... and tasks with the Linux watch command.md | 123 +++++++++++++++++ 2 files changed, 123 insertions(+), 124 deletions(-) delete mode 100644 sources/tech/20210916 Watch commands and tasks with the Linux watch command.md create mode 100644 translated/tech/20210916 Watch commands and tasks with the Linux watch command.md diff --git a/sources/tech/20210916 Watch commands and tasks with the Linux watch command.md b/sources/tech/20210916 Watch commands and tasks with the Linux watch command.md deleted file mode 100644 index ec01b2f5ad..0000000000 --- a/sources/tech/20210916 Watch commands and tasks with the Linux watch command.md +++ /dev/null @@ -1,124 +0,0 @@ -[#]: subject: "Watch commands and tasks with the Linux watch command" -[#]: via: "https://opensource.com/article/21/9/linux-watch-command" -[#]: author: "Moshe Zadka https://opensource.com/users/moshez" -[#]: collector: "lujun9972" -[#]: translator: "geekpi" -[#]: reviewer: " " -[#]: publisher: " " -[#]: url: " " - -Watch commands and tasks with the Linux watch command -====== -See how the watch command can let you know when a task has been -completed or a command has been executed. -![Clock, pen, and notepad on a desk][1] - -There are many times when you need to wait for something to finish, such as: - - * A file download. - * Creating or extracting a [tar][2] file. - * An [Ansible][3] job. - - - -Some of these processes have some sort of progress indication, but sometimes the process is run through a layer of abstraction, and the only way to measure the progress is through its side effects. Some of these might be: - - * A file being downloaded keeps growing. - * A directory extracted from a tarball fills up with files. - * The Ansible job builds a [container][4]. - - - -You can query all of these things with commands like these: - - -``` -$ ls -l downloaded-file -$ find . | wc -l -$ podman ps -$ docker ps -``` - -But running these commands over and over, even if it is with the convenience of [Bash history][5] and the **Up Arrow**, is tedious. - -Another approach is to write a little Bash script to automate these commands for you: - - -``` -while : -do -  docker ps -  sleep 2 -done -``` - -But such scripts can also become tedious to write. You could write a little generic script and package it, so it's always available to you. Luckily, other open source developers have already been there and done that. - -The result is the command `watch`. - -### Installing watch - -The `watch` command is part of the [`procps-ng` package][6], so if you're on Linux, you already have it installed. - -On macOS, install `watch` using [MacPorts][7] or [Homebrew][8]. On Windows, use [Chocolatey][9]. - -### Using watch - -The `watch` command periodically runs a command and shows its output. It has some text-terminal niceties, so only the latest output is on the screen. - -The simplest usage is: `watch `. - -For example, prefixing the `docker ps` command with `watch` works like this: - - -``` -`$ watch docker ps` -``` - -The `watch` command, and a few creative Unix command-line tricks, can generate ad-hoc dashboards. For example, to count audit events: - - -``` -`$ watch 'grep audit: /var/log/kern.log |wc -l'` -``` - -In the last example, it is probably useful if there's a visual indication that the number of audit events changed. If change is expected, but you want something to look "different," `watch --differences` works well. It highlights any differences from the last run. This works especially well if you are grepping in multiple files, so you can easily see which one changed. - -If changes are not expected, you can ask for them to be highlighted "permanently" to know which ones to investigate by using `watch --differences=permanent`. This is often more useful. - -### Controlling frequency - -Finally, sometimes the command might be resource-intensive and should not be run too frequently. The `-n` parameter controls the frequency. Watch uses two seconds by default, but `watch -n 10` might be appropriate for something more resource-intensive, like grepping for a pattern in any file in a subdirectory: - - -``` -`$ watch -n 10 'find . -type f | xargs grep suspicious-pattern'` -``` - -### Watch a command with watch - -The `watch` command is useful for many ad-hoc system administration tasks where you need to wait for some time-consuming step, without a progress bar, before moving on to the next one. Though this is not a great situation to be in, `watch` can make it slightly better—and give you time to start working on those notes for the retrospective! Download the **[cheat sheet][10] **to keep helpful syntax and options close at hand. - --------------------------------------------------------------------------------- - -via: https://opensource.com/article/21/9/linux-watch-command - -作者：[Moshe Zadka][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/moshez -[b]: https://github.com/lujun9972 -[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/desk_clock_job_work.jpg?itok=Nj4fuhl6 (Clock, pen, and notepad on a desk) -[2]: https://opensource.com/article/17/7/how-unzip-targz-file -[3]: https://opensource.com/resources/what-ansible -[4]: https://opensource.com/resources/what-docker -[5]: https://opensource.com/article/20/6/bash-history-control -[6]: https://opensource.com/article/21/8/linux-procps-ng -[7]: https://opensource.com/article/20/11/macports -[8]: https://opensource.com/article/20/6/homebrew-mac -[9]: https://opensource.com/article/20/3/chocolatey -[10]: https://opensource.com/downloads/watch-cheat-sheet diff --git a/translated/tech/20210916 Watch commands and tasks with the Linux watch command.md b/translated/tech/20210916 Watch commands and tasks with the Linux watch command.md new file mode 100644 index 0000000000..60226c9c42 --- /dev/null +++ b/translated/tech/20210916 Watch commands and tasks with the Linux watch command.md @@ -0,0 +1,123 @@ +[#]: subject: "Watch commands and tasks with the Linux watch command" +[#]: via: "https://opensource.com/article/21/9/linux-watch-command" +[#]: author: "Moshe Zadka https://opensource.com/users/moshez" +[#]: collector: "lujun9972" +[#]: translator: "geekpi" +[#]: reviewer: " " +[#]: publisher: " " +[#]: url: " " + +用 Linux 的 watch 命令观察命令和任务 +====== +了解 watch 命令如何让你知道任务已完成或命令已执行。 +![Clock, pen, and notepad on a desk][1] + +有很多时候，你需要等待一些事情的完成，比如： + + * 一个文件的下载。 + * 创建或解压一个 [tar][2] 文件。 + * 一个 [Ansible][3] 作业。 + + + +其中一些进程有进度指示，但有时进程是通过一层抽象运行的，衡量进度的唯一方法是通过其副作用。其中一些可能是： + + * 一个正在下载的文件不断增长。 + * 一个从 tarball 中提取的目录被文件填满了。 + * Ansible 作业构建了一个[容器][4]。 + + + +你可以用这样的命令查询所有这些： + + +``` +$ ls -l downloaded-file +$ find . | wc -l +$ podman ps +$ docker ps +``` + +但是反复运行这些命令，即使是利用 [Bash 历史][5]和**向上箭头**的便利，也是很乏味的。 + +另一种方法是写一个小的 Bash 脚本来为你自动执行这些命令： + + +``` +while : +do + docker ps + sleep 2 +done +``` + +但这样的脚本写起来也会很繁琐。你可以写一个小的通用脚本，并将其打包，这样它就可以一直被你使用。幸运的是，其他开源的开发者已经有了这样的经验和做法。 + +那就是 `watch` 这个命令。 + +### 安装 watch + +`watch` 命令是 [`procps-ng` 包][6]的一部分，所以如果你是在 Linux 上，你已经安装了它。 + +在 macOS 上，使用 [MacPorts][7] 或 [Homebrew][8] 安装 `watch`。在 Windows 上，使用 [Chocolatey][9]。 + +### 使用 watch + +`watch` 命令定期运行一个命令并显示其输出。它有一些文本终端的特性，所以只有最新的输出才会出现在屏幕上。 + +最简单的用法是：`watch `。 + +例如，在 `docker ps` 命令前加上 `watch`，就可以这样操作： + + +``` +`$ watch docker ps` +``` + +用 `watch` 命令，以及一些创造性的 Unix 命令行技巧，可以生成临时的仪表盘。例如，要计算审计事件： + + +``` +`$ watch 'grep audit: /var/log/kern.log |wc -l'` +``` + +在最后一个例子中，如果有一个可视化的指示，表明审计事件的数量发生了变化，这可能是有用的。如果变化是预期的，但你想让一些东西看起来“不同”，`watch --differences` 就很好用。它可以高亮显示与上次运行的任何差异。如果你在多个文件中搜索，这一点尤其有效，所以你可以很容易地看到哪个文件发生了变化。 + +如果没有预期的变化，你可以使用 `watch --differences=permanent` 要求它们被“永久”高亮显示，以便知道哪些变化需要调查。这通常是更有用的。 + +### 控制频率 + +最后，有时该命令可能是资源密集型的，不应运行得太频繁。`-n` 参数控制频率。Watch 默认使用 2 秒，但是 `watch -n 10` 可能适合于资源密集型的情况，比如在子目录的任何文件中搜索一个模式： + + +``` +`$ watch -n 10 'find . -type f | xargs grep suspicious-pattern'` +``` + +### 用 watch 观察一个命令 + +`watch` 命令对于许多临时性的系统管理任务非常有用，在这些任务中，你需要在没有进度条的情况下等待一些耗时的步骤，然后再进入下一个步骤。尽管这种情况并不理想，但 `watch` 可以使情况稍微好转。它让你有时间为工作做回顾性笔记！"。下载**[备忘录][10]**，让有用的语法和选项触手可及。。 + +-------------------------------------------------------------------------------- + +via: https://opensource.com/article/21/9/linux-watch-command + +作者：[Moshe Zadka][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://opensource.com/users/moshez +[b]: https://github.com/lujun9972 +[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/desk_clock_job_work.jpg?itok=Nj4fuhl6 (Clock, pen, and notepad on a desk) +[2]: https://opensource.com/article/17/7/how-unzip-targz-file +[3]: https://opensource.com/resources/what-ansible +[4]: https://opensource.com/resources/what-docker +[5]: https://opensource.com/article/20/6/bash-history-control +[6]: https://opensource.com/article/21/8/linux-procps-ng +[7]: https://opensource.com/article/20/11/macports +[8]: https://opensource.com/article/20/6/homebrew-mac +[9]: https://opensource.com/article/20/3/chocolatey +[10]: https://opensource.com/downloads/watch-cheat-sheet