Scheduling Repetitive Jobs: crontab

You can schedule routine system administration commands to execute daily, weekly, or monthly by using the crontab commands.

Daily crontab system administration tasks might include:

• Removing junk files more than a few days old from temporary directories

• Executing accounting summary commands

• Taking snapshots of the system by using df and ps commands

• Performing daily security monitoring

• Running system backups

Weekly crontab system administration tasks might include:

• Rebuilding the catman database for use by man -k

• Running fsck -n to list any disk problems

Monthly crontab system administration tasks might include:

• Listing files not used that month

• Producing monthly accounting reports

Additionally, users can schedule crontab commands to execute other routine system tasks, such as sending reminders and removing backup files.

For more information about scheduling crontab jobs, see Chapter 30, Scheduling System Events (Tasks).