Hello Dani,
Mac OS X is a *nix, and it has a crontab just like Linux and the rest of them. If you take a look at /etc/crontab, it will show you that these scripts are called regularly.
Here is mine:
yoda:/etc Christian$ cat crontab
# /etc/crontab
SHELL=/bin/sh
PATH=/etc:/bin:/sbin:/usr/bin:/usr/sbin
HOME=/var/log
#
#minute hour mday month wday who command
#
#*/5 * * * * root /usr/libexec/atrun
#
# Run daily/weekly/monthly jobs.
15 3 * * * root periodic daily
30 4 * * 6 root periodic weekly
30 5 1 * * root periodic monthly
The order of the colums are:
MINUTE HOUR DAY MONTH WEEKDAY USER "ACTUAL COMMAND"
So, according to my line, I am running the daily at 3:15am (the times are in 24 hour clocks), the weekly runs on a Saturday (1=Mon, 2=Tue, 6=Sat), and the monthly happens on the 1st of the month, at 5:30 in the morning.
Yes, these are just like the familiar /etc/daily and /etc/monthly that you are familiar with.
Honestly, nearly all of the Mac users out there will not be aware of these files, and what they do. Apple has done well keeping things GUI based, but for us intense computer people, the Unix kernel is well... sexy.
Great question Dani. Good to see ya.
Christian