From 14863acd2a25d40e4c5f1c2ffc20fba253dcd41d Mon Sep 17 00:00:00 2001 From: perfiffer Date: Fri, 30 Jul 2021 10:03:34 +0800 Subject: [PATCH] translated --- .../tech/20210726 How to use cron on Linux.md | 116 ------------------ .../tech/20210726 How to use cron on Linux.md | 108 ++++++++++++++++ 2 files changed, 108 insertions(+), 116 deletions(-) delete mode 100644 sources/tech/20210726 How to use cron on Linux.md create mode 100644 translated/tech/20210726 How to use cron on Linux.md diff --git a/sources/tech/20210726 How to use cron on Linux.md b/sources/tech/20210726 How to use cron on Linux.md deleted file mode 100644 index f60772bc4e..0000000000 --- a/sources/tech/20210726 How to use cron on Linux.md +++ /dev/null @@ -1,116 +0,0 @@ -[#]: subject: (How to use cron on Linux) -[#]: via: (https://opensource.com/article/21/7/cron-linux) -[#]: author: (Seth Kenlon https://opensource.com/users/seth) -[#]: collector: (lujun9972) -[#]: translator: (perfiffer) -[#]: reviewer: ( ) -[#]: publisher: ( ) -[#]: url: ( ) - -How to use cron on Linux -====== -The cron system is a method to automatically run commands on a schedule. -![Cron expression][1] - -The cron system is a method to automatically run commands on a schedule. A scheduled job is called a _cronjob_, and it’s created in a file called a _crontab_. It’s the easiest and oldest way for a computer user to automate their computer. - -### Writing a cronjob - -To create a cronjob, you edit your `crontab` using the `-e` option: - - -``` -`$ crontab -e` -``` - -This opens your crontab your default text editor. To set the text editor explicitly, use the `EDITOR` [environment variable][2]: - - -``` -`$ EDITOR=nano crontab -e` -``` - -### Cron syntax - -To schedule a cronjob, you provide the command you want your computer to execute, followed by a cron expression. The cron expression schedules when the command gets run: - - * minute (0 to 59) - - * hour (0 to 23, with 0 being midnight) - - * day of month (1 to 31) - - * month (1 to 12) - - * day of week (0 to 6, with Sunday being 0) - - - - -An asterisk (`*`) in a field translates to "every." For example, this expression runs a backup script at the 0th minute of _every_ hour on _every_ day of _every_ month: - - -``` -`/opt/backup.sh 0 * * * *` -``` - -This expression runs a backup script at 3:30 AM on Sunday: - - -``` -`/opt/backup.sh 30 3 * * 0` -``` - -### Simplified syntax - -Modern cron implementations accept simplified macros instead of a cron expression: - - * `@hourly` runs at the 0th minute of every hour of every day - - * `@daily` runs at the 0th minute of the 0th hour of every day - - * `@weekly` runs at the 0th minute of the 0th hour on Sunday - - * `@monthly` runs at the 0th minute of the 0th hour on the first day of the month - - - - -For example, this crontab line runs a backup script every day at midnight: - - -``` -`/opt/backup.sh @daily` -``` - -### How to stop a cronjob - -Once you've started a cronjob, it's designed to run on schedule forever. To stop a cronjob once you've started it, you must edit your crontab, remove the line that triggers the job, and then save the file. - - -``` -`$ EDITOR=nano crontab -e` -``` - -To stop a job that's actively running, [use standard Linux process commands][3] to stop a running process. - -### It’s automated - -Once you’ve written your crontab, save the file and exit your editor. Your cronjob has been scheduled, so cron does the rest. - --------------------------------------------------------------------------------- - -via: https://opensource.com/article/21/7/cron-linux - -作者：[Seth Kenlon][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/seth -[b]: https://github.com/lujun9972 -[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/cron-splash.png?itok=AoBigzts (Cron expression) -[2]: https://opensource.com/article/19/8/what-are-environment-variables -[3]: https://opensource.com/article/18/5/how-kill-process-stop-program-linux diff --git a/translated/tech/20210726 How to use cron on Linux.md b/translated/tech/20210726 How to use cron on Linux.md new file mode 100644 index 0000000000..8c0ad94b3c --- /dev/null +++ b/translated/tech/20210726 How to use cron on Linux.md @@ -0,0 +1,108 @@ +[#]: subject: (How to use cron on Linux) +[#]: via: (https://opensource.com/article/21/7/cron-linux) +[#]: author: (Seth Kenlon https://opensource.com/users/seth) +[#]: collector: (lujun9972) +[#]: translator: (perfiffer) +[#]: reviewer: ( ) +[#]: publisher: ( ) +[#]: url: ( ) + +在 Linux 上怎么使用 cron 定时器 +====== +cron 定时器是一个可以按照计划自动运行命令的工具。 +![Cron 表达式][1] + +cron定时器是一个可以按照计划自动运行命令的工具。这个定时器作业被叫做 cronjob，它被创建在 crontab 文件中。这是用户自动操作电脑的最简单也是最古老的方法。 + +### 创建一个 cronjob + +要创建一个 cronjob，你可以使用 crontab 命令，并添加 `-e` 选项： + +``` +`$ crontab -e` +``` + +这会使用默认的文本编辑器打开 crontab。要显示设置文本编辑器，请使用 `EDITOR` [环境变量][1]： + +``` +`$ EDITOR=nano crontab -e` +``` + +### Cron 语法 + +要调度一个 cronjob，你需要提供给计算机你想要执行的命令，然后提供一个 cron 表达式。cron 表达式在命令调度时运行： + + * minute (0 到 59) + + * hour (0 到 23, 0 代表午夜执行) + + * day of month (1 到 31) + + * month (1 到 12) + + * day of week (0 到 6, 星期天是 0) + + + +星号 （`*`） 代表的是“每一个”。例如，下面的表达式在每月每日每小时的 0 分钟运行备份脚本： + +``` +`/opt/backup.sh 0 * * * *` +``` + +下面的表达式在周日的凌晨 3:30 运行备份脚本： + +``` +`/opt/backup.sh 30 3 * * 0` +``` + +### 简写语法 + +现代的 cron 实现接收简化的宏，而不是 cron 表达式： + + * `@hourly` 在每天的每小时的 0 分运行 + + * `@daily` 在每天的 0 时 0 分运行 + + * `@weekly` 在周日的 0 时 0 分运行 + + * `@monthly` 在每月的第一天的 0 时 0 分运行 + + + +例如，下面的 crontab 命令在每天的 0 时运行备份脚本： + +``` +`/opt/backup.sh @daily` +``` + +### 如何停止一个 cronjob + +一旦你开始了一个 cronjob，它就会永远按照计划运行。想要在启动后停止 cronjob，你必须编辑 crontab，删除触发该作业的命令行，然后保存文件。 + +``` +`$ EDITOR=nano crontab -e` +``` + +要停止一个正在运行的作业，可以[使用标准的Linux进程命令][3]来停止一个正在运行的进程。 + +### 它是自动的 + +一旦你编写完 crontab，保存了文件并且退出了编辑器。你的 cronjob 就已经被调度了，剩下的工作都由 cron 完成。 + +-------------------------------------------------------------------------------- + +via: https://opensource.com/article/21/7/cron-linux + +作者：[Seth Kenlon][a] +选题：[lujun9972][b] +译者：[perfiffer](https://github.com/perfiffer) +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 +[b]: https://github.com/lujun9972 +[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/cron-splash.png?itok=AoBigzts (Cron expression) +[2]: https://opensource.com/article/19/8/what-are-environment-variables +[3]: https://opensource.com/article/18/5/how-kill-process-stop-program-linux