# Crontab - Notes ## Structure ![](https://i.imgur.com/v6v7VbJ.png) ## Predefined : * @yearly (or @annually) - Run the specified task once a year at midnight (12:00 am) of the 1st of January. Equivalent to 0 0 1 1 *. * @monthly - Run the specified task once a month at midnight on the first day of the month. Equivalent to 0 0 1 * *. * @weekly - Run the specified task once a week at midnight on Sunday. Equivalent to 0 0 * * 0. * @daily - Run the specified task once a day at midnight. Equivalent to 0 0 * * *. * @hourly - Run the specified task once an hour at the beginning of the hour. Equivalent to 0 * * * *. * @reboot - Run the specified task at the system startup --- ## Systemwide Crontab ```/etc/crontab``` : ``` * * * * * <username> command(s) ``` ## Using Crontab Cli : ![](https://i.imgur.com/CRiPLSQ.png) ## Examples : [click here](https://linuxize.com/post/scheduling-cron-jobs-with-crontab/#cron-jobs-examples)