如何在Linux系统上每天运行Cron作业

本文将教您如何安排玉米作业，以便每天在特定时间执行脚本，命令或Shell脚本。作为系统管理员，我们知道在后台自动运行例行维护作业的重要性。Linux corn实用程序将帮助我们维护这些作业以在后台运行。

Cron作业的一般语法

MIN HOUR Day of month Month Day of Week Command

0-59 0-23 1-31 1-12 0-6 Any Linux command or script

要查看机器上存在的cron作业列表，请运行以下命令–

# crontab -l

no crontab for root

要添加新的cron作业，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

添加以下示例，每天在11:00执行指定的日志备份Shell脚本。我们可以在一个字段中指定逗号分隔的值，该字段指定脚本需要在所有提到的时间内执行。

00 11 * * * /home/backups/scripts/log_backup.sh

结论：在配置结束时，您可以每天在特定时间运行脚本或命令，这样我们可以使用逗号分隔值指定多次执行的时间。