Crontab – Quick Reference

Cron is a time-based job scheduler in linux/Unix based system. It is also same as scheduler in windows. Cron enables users to schedule jobs (commands or shell scripts) to run automatically at a certain time or date. It is commonly used to automate system maintenance or administration, though its general purpose nature means that it can be used for other purposes, such as connecting to the Internet and downloading email.

Crontab file
Crontab syntax :
A crontab file has five fields for specifying day , date and time followed by the command to be run at that interval.

*     *   *  *   *  command to be executed -     -    -   -  - |     |     |   |    | |     |     |   |    +----- day of week (0 - 6) (Sunday=0) |     |     |   +------- month (1 - 12) |     |     +--------- day of month (1 - 31) |     +----------- hour (0 - 23) +------------- min (0 - 59)

^{Normally on cPanel server, you can easily set cron. Just login to cpanel and click on cron jobs. You will have graphical interface to set cron job.}