I keep wondering whether there's a job scheduler for me too, but not finding much. At work I'm using/writing a custom one: with multiple schedules in crontab fo

I keep wondering whether there's a job scheduler for me too, but not finding much. At work I'm using/writing a custom one: with multiple schedules in crontab format for each task, frequent automated task updates (by an identifier) from multiple sources, additional flags for some jobs to not run if the parameters didn't change, and/or to rerun every few hours to ensure that proper states are set. It still felt like a generic enough task to use an external tool with those requirements, but then additional functionality appeared, such as changing task parameters according to certain rules (and internal state). At this point it seems that the way to go is either a custom scheduler or just regular cron, crontab editing, and wrappers akin to cronic (or otherwise handling the state-related configuration in the tasks it runs) -- that is, also a custom scheduling system, but incorporating cron. Here cron's simplicity seems fine: say, prevention of duplicate tasks should be by those "task group" IDs, rather than just jobs listed in crontab (so even if cron had the latter, it wouldn't be useful).