centre{source}

Debian has some handy directories for dropping scripts into regular cron rotation, /etc/cron.hourly/, /etc/cron.daily/, /etc/cron.weekly/ and /etc/cron.monthly/.

I spent a long time wondering (but never really looking) into why certain update scripts I had in there weren’t running. Turns out these scripts are called via “run-parts”, and, well, turns out it’s my stupid fault for not reading the manpage, which makes it pretty clear:

RUN-PARTS(8):

run-parts runs a number of scripts or programs found in a
single directory directory. Filenames should consist
entirely of upper and lower case letters, digits, under­
scores, and hyphens. Subdirectories of directory and
files with other names will be silently ignored.

My script’s name? “check-apt.sh”, which puts it into the “silently ignored” category. Lesson learned — always read the man pages, kids.