Run three different cron jobs twice in hour

Question

I want to run three cron jobs commands twice per hour (once every half hour) and the interval between these command should be 1-2 minutes. How should I configure cron jobs from cpanel?

Answer 1

I can't speak for cpanel, I'm afraid, but the crontab entries (if you can get to those) should look like this:

1,31 * * * *  /path/job1
3,33 * * * *  /path/job2
5,35 * * * *  /path/job3

That'll run each twice an hour, at 1, 3, and 5 minutes past the hour and half-hour.

Answer 2

The interval between starting the jobs should be 2 minutes, or the interval from after one finishes 'til the next one starts should be 2 minutes?

If it's the first case, see MadHatter's comment.

If it's the second case, it's easiest to wrap the whole thing in a shell script, and do sleep 120 in between.

I'll often do this if the next task shouldn't fire off if the previous task didn't return cleanly. It also makes it easier to set a semaphore for the whole group of tasks so if a task gets hung, the next time it runs, you don't kick off the tasks again.