Crontab

Crontab is a utility you can use to schedule jobs that need to run on a schedule, such as a nightly MySQL Backups.

A good source of documentation for Crontab is:

http://www.adminschoice.com/docs/crontab.htm

One important thing to note when creating scripts that will be run from crontab is that you need to fully qualify any reference to programs outside of the /bin directory (so anything in /usr/bin needs to be fully qualified – like /usr/bin/mysqldump).