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.