Crontab periodic task

Crontab usage:

Crontab [-u user] File

Crontab [-u user] {-L |-r |-e}

-L: displays the content of the crontab file.

-E: Use Vim to edit the crontab file.

-I: Confirmation prompt before deleting the user crontab file.

-R: Delete the crontab file from the crontab directory.

(Crontab-ri)

-U User: Specifies the user.

/Etc/cron. deny: users in the file cannot use the crontab command.

/Etc/cron. allow: users in the file can use the crontab command.

/Var/spool/cron: directory where all user crontab files are stored.

Crontab file format:

* *** Root run-parts/etc/cron. Hourly

Week (0 indicates Sunday)

You can omit

Symbol: * any time

-Time range (2-7 points)

, Split the time range (and)

/N every n units of time (*/10 indicates that every 10 minutes is equivalent to 0-59/10)

Crontab dependent service: chkconfig -- list | grep 3: On

/Etc/init. d/crond status (Check service status)

Crontab periodic task