Linux cron is a daemon that can be used to schedule the execution of recurring tasks according to a combination of the time, day of the month, month, day of the week, and week.
Your Linux computer should be running continuously to use the cron deamon properly. If the Linux computer is not on when a task is scheduled, it is not executed
The Linux cron command is very useful, if you want to schedule a job, when you are away from your office, like bakup jobs.
To use the cron service in a RedHat Enterprise Linux computer, you must have the vixie-cron RPM package installed, and the crond service must be running. To determine if the package is installed, use the rpm -q vixie-cron command. To determine if the service is running, use the command /sbin/service crond status.