Unix System Management: scheduling cron tasks

To complete this palm, you can do the following things:

Use cron to submit, list, and delete time schedule tasks.

Schedule full and incremental backups to run automatically.

Let non roothttp://www.aliyun.com/zixun/aggregation/6579.html "> users use cron

14.1 Cron Daemon

-cron Daemon

To execute a command at a specified date and time

Automate daily tasks

Example：

-Trim the system's log files

-Perform system backups

-Generate weekly reports

System administrators usually need to do backup and run other processes every day, weekly, monthly. Although these processes can be run manually, they usually need to be scheduled to run automatically. The cron daemon works with this.

The cron daemon starts when the system boots and the system administrator and other users perform a time scheduling task submission.

You can use the PS command to check if the cron daemon is running.

# Ps–ef |grep cron #cron正在运行吗?

# cron # If not running, start the cron daemon.

As root, regular users can also use Cron to run programs repeatedly. The task to be performed is submitted to cron execution through the crontab command. Root uses the/var/adm/cron/cron.allow file to control who has access to the crontab command. If the user's name appears in the Cron.allow file, he has the right to use the crontab command. If the Cron.allow file does not exist, the system checks the/var/adm/cron/cron.deny file to determine if the user is denied access. If all two files exist, Cron.allow has precedence. If two files do not exist, only root can submit the task. If the Cron.deny file is an empty file, all users can use crontab.

*.allow *.deny

Who can use it?

－ －

exist ignore

-Existing

Null ignored

-NULL

Super User

Any user in *.allow

No users in *.deny

Super User

Each user