KCron

常规信息

KCron是个定期在后台运行程序的工具。他是Cron命令的图形界面。 KCron是个标准的KDE工作区应用程序。

Task Scheduler is a graphical front end to the standard "cron" utility. With it, commands (or "tasks") can be run at specific times, on a certain day or date, or at specific intervals (time between execution).

Task Scheduler in Plasma 5

用法

到了KDE 4.4 中KCron 是系统设定-> 高阶-> 系统 -> 任务调度 的模组。如果没找到，请检查是否已安装kdeadmin 包。 KDE 4.5 中是在 系统设定-> 系统管理员-> 任务调度 。一些发行版将 KCron单独弄成一个包，所以你得自己找找。

Adding and Modifying tasks

• Click New Task... to add a new task, or "Modify" to modify an existing task. The Add or modify existing task page will be displayed.

The "Add or modify task" page of SystemSettings

• Enter the command to be run. Click the folder icon to choose it from a dialog.

• Enter a comment (optional). This should be descriptive, explaining what the task will do as the command may not always be obvious.

• Click Enable this task to enable the task to run.

• Click Run at system bootup to enable the script to run each time the system is booted.

• Click Run every day to enable the script to run every day. This will automatically select the appropriate options.

• Using the buttons, choose when the command should be run. Not all parameters are required, those not needed may be left blank.
  • Hours and Minutes are the time of day to run the task, not an interval.

• When done, click OK. The task will be added and scheduled if enabled.

Tip

Click Run Now to run a task immediately after adding or modifying the task.

Removing a task

To completely remove a task, select the task from the list and click the Delete button. This will permanently remove the task.

Environment Variables

Sometimes a task or multiple tasks need a specific variable set, it must be added in the Environment Variables section. The cron utility uses its own environment, system-wide and user-specific variables are not used. Click New Variable to add a new variable definition, or Modify to change an existing variable.

• Enter the name of the variable to use. This name:
  • Must consist of letters, digits, and underscore ('_') only
  • Must start with a letter
  • Should not be a reserved or commonly used system variable. See https://pubs.opengroup.org/onlinepubs/000095399/basedefs/xbd_chap08.html for more information

• The value the variable will contain. This can be a number or string.

• Enter a brief description of the variable.

提示

• 全部修改的文件都位于拥有许多文件的/etc/cron目录。

• 查看现在安装好的cron任务的命令行工具是

  crontab -l

  （小写的字母L）

More Information

• KDE official documentation
• Cron (Wikipedia)
• Cron (Arch Linux wiki)