crontab every 3 hours code example
Example 1: cron every 3 hours
0 */3 * * *
Example 2: crontab every 30 minutes between hours
// from 08h to 17h (until 17:30)
*/30 8-17 * * *
// from 08h to 17h, at number '5' (until 17:35)
5,30 8-17 * * *
Example 3: cron every two hours
0 */2 * * *