Linux

10.6    Starting Processes Automatically (Cron)

If your computer suddenly—seemingly unexpectedly—starts to search the hard disk or SSD, sends you emails, and so on, then the cause is almost always the automatic launch of processes through the Cron daemon.

This program is started automatically by the init process when the computer boots. It becomes active once per minute, analyzes all crontab files, and launches the programs specified there. Cron is primarily used for maintenance tasks: to compress and archive logging files, to delete temporary files, to update directories, to perform backups, and so on.

The global configuration of Cron is done by the /etc/crontab file. In addition, users are allowed to define their own cron jobs in the user-specific ...