Cron is the ability to run programs based on the system clock. A cronjob is a scheduled task that you want to automatically run at a scheduled time, e.g. run my backup at 7:30pm everyday. You need to create a cron table or "crontab", a file of dates and commands that you want to run. A crontab file instructs the system to run specific commands at a given time. Run unlimited cronjobs a day. You may setup your own cron jobs within your Cpanel administration area.