How do I list all cron jobs for all users?

Question

Is there a command or an existing script that will let me view all of a *NIX system's scheduled cron jobs at once? I'd like it to include all of the user crontabs, as well as /etc/crontab, and whatever's in /etc/cron.d. It would also be nice to see the specific commands run by run-parts in /etc/crontab.

Ideally, I'd like the output in a nice column form and ordered in some meaningful way.

I could then merge these listings from multiple servers to view the overall "schedule of events."

I was about to write such a script myself, but if someone's already gone to the trouble...

Answer 1

You would have to run this as root, but:

for user in $(cut -f1 -d: /etc/passwd); do crontab -u $user -l; done 

will loop over each user name listing out their crontab. The crontabs are owned by the respective users so you won't be able to see another user's crontab w/o being them or root.

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Edit if you want to know which user a crontab belongs to, use echo $user

for user in $(cut -f1 -d: /etc/passwd); do echo $user; crontab -u $user -l; done