I'm trying to run cron jobs to start any inhibited processes after a system reboot.
I can schedule th cron, but i'm confused as to how to incorporated the reboot, since reboot is scheduled at different times, once every month.
How can I write this to start every 15 min after after a reboot
It depends on which cron daemon you use as not all support this. I know vixie-cron allows scheduling jobs at reboot and you could put the 15 minute sleep into your script which restarts these processes, I'm not too sure about other crons.