how to run cron job every 3 months?
Solution 1:
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.
Solution 2:
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
Solution 3:
The accepted answer is good, thou I'd use an alternative with simpler numbers and easier to read: https://crontab.guru
0 0 1 */3 *
Read like this: “At 00:00 on day-of-month 1 in every 3rd month.”