In Linux, tasks can be configured to run automatically within a given period of time and on given dates. Red Hat Linux comes preconfigured to run certain system tasks to keep your system updated. For example, the slocate database is updated daily. A system administrator can use automated tasks to perform periodic backups, monitor the system, run custom scripts, and more.
Cron is a daemon that can be used to execute scheduled tasks according to a combination of the time, day of the month, month, day of the week, and week.
Cron assumes that the system is on continuously. If the system is not on when a task is scheduled it is not executed. To configure tasks based on periods instead of exact times, see the section called Anacron.
To use the cron service, you must have the vixie-cron RPM package installed. To determine if the package is installed, use the command rpm -q vixie-cron.