Cron jobs are perfect for repetitive tasks that need to be run on every hour, day, week, or month.

Cron jobs are stored in a file, known as crontab (short for cron table). The syntax is as follows:

* * * * * command to be executed
min, hour, day of month, month, day of week, command to be executed

To create a new crontab, or edit the existing crontab for the user currently logged in:

crontab -e 

If you add tasks to this crontab, then the process will be owned by the user which is currently logged in.

export EDITOR=nano

To display your crontab:

crontab -l 

To remove all cron jobs (remove the entire crontab):

crontab -r

To set up a Crob job on your account, do the following:

1. Sign in to Virtualmin (see Account logins and important URLs).
2. Click Webmin in the upper-left hand corner, the System, then Scheduled Cron Jobs.
3. Click Create a new scheduled cron job.
4. Enter the full command to run (including command arguments) into the Command field. Don’t forget to specify full paths to all binaries (e.g. /usr/local/bin/php instead of just php).
5. Enter a textual description into Description. This is optional but will help you identify cron jobs later on.
6. Select an execution schedule. The default setting will create a cron job that executes every hour. The options that you select from the list fields will set a time when the job will execute (unless you have the All option select which ignores the particular select list).
7. When you are done, click Create.