Many times we need to have some process to run automatically at set times or after set intervals. This can be easily done in Linux/Unix by using cron jobs. In this post I’ll talk cron and crontabs. Cron is an Unix utility which allows you to automatically run tasks periodically at set times or set time intervals. crontab is a file which contains the details of which task has to be run when. It is essentially a schedule of all crons.