如何在 Linux 中创建 Cron 任务并在指定时间执行


在本文中,我们将教您如何安排一个将在指定时间执行的 corn 任务。

Cron 任务的一般语法

MIN    HOUR    Day of month    Month    Day of Week    Command
0-59   0-23       1-31          1-12       0-6       linux command or script

要查看机器上存在的 Cron 任务列表,请运行以下命令 –

# crontab -l
no crontab for root

要添加新的 Cron 任务,请运行以下命令 –

#crontab -e
no crontab for root - using an empty one
Select an editor. To change later, run 'select-editor'.
1. /bin/ed
2. /bin/nano <---- easiest
3. /usr/bin/vim.basic
4. /usr/bin/vim.tiny
Choose 1-4 [2]:2
# Edit this file to introduce tasks to be run by cron.
#
# Each task to run has to be defined through a single line
# indicating with different fields when the task will be run
# and what command to run for the task
#
# To define the time you can provide concrete values for
# minute (m), hour (h), day of month (dom), month (mon),
# and day of week (dow) or use '*' in these fields (for 'any').#
# Notice that tasks will be started based on the cron's system
# daemon's notion of time and timezones.
#
# Output of the crontab jobs (including errors) is sent through
# email to the user the crontab file belongs to (unless redirected).
#
# For example, you can run a backup of all your user accounts
# at 5 a.m every week with:
# 0 5 * * 1 tar -zcf /var/backups/home.tgz /home/
#
# For more information see the manual pages of crontab(5) and cron(8)
#
# m h dom mon dow command

为某个特定时间安排任务

Cron 的基本用法是按如下所示在某个指定时间执行任务。这将在 4 月 20 日下午 6:40 执行全备份 shell 脚本 (full-backup)。

40 18 20 04 * /home/backups/full-backup

解释

40 – 40th Minute
18 – 06 PM
20 – 20th Day
04 – 4th Month (April)
* – Every day of the week

在配置的最后,你将能够在每一天的某个特定时间运行一个脚本或命令,比如这样,我们可以使用逗号分隔值指定多个执行时间。

更新于: 2020-01-21

2 千 + 查看量

开启你的职业生涯

通过完成课程获得认证

开始吧
广告
© . All rights reserved.