how to run cron job every 3 months?

The following will run script on the 1st of Jan, Apr, Jul and Oct at 03:30

30 03 01 Jan,Apr,Jul,Oct * /path/to/script

Alternatively, but less obvious

30 03 01 */3 * /path/to/script

Will run every three months at 03:30 on the 1st of Jan,Apr,Jul and Oct.

Wikipedia has a nice explanation about how to configure Cron.

For your specific case you could run a Cron Expression to run every 3 months- obviously change the months to suit your schedule.

0 0 1 JAN,APR,JUL,OCT  * /path/to/script.bash

Related