Get a list of all the cron jobs on a Debian based system

I’m sure you have one time or another wondered where all the magic is happening on your servers.

Anything from how and why the logs are rotated, why your desktop icon says “20 packages can now be updated”, how is the Apache cache cleaned when you’re using mod_cache and so on.

You’ve also probably know about this thing called cron, that there are several places and ways to add cron jobs. But do you know about them all? Have you had a look at everything that all the users have set up in their personal crontabs (what, do I have my personal crontab?), what the “at” command has set up (that’s just a magic command, isn’t it?), in addition to the root user’s /etc/crontab and the cron.* directories?

find /var/spool/cron/ /etc/cron* -name "cron*" |  \
while read d; do find $d -type f; done | \
egrep -v '.(placeholder|.SEQ)$' | \
sort | \