CRON(8) MachTen Programmer’s Manual CRON(8)

NAME
cron - daemon to execute scheduled commands (Vixie Cron)

SYNOPSIS
cron

DESCRIPTION
Cron should be started from /etc/rc or /etc/rc.local. It
will return immediately, so you don’t need to start it
with ’&’.

Cron searches /var/cron/tabs for crontab files which are
named after accounts in /etc/passwd; crontabs found are
loaded into memory. Cron also searches for /etc/crontab
which is in a different format (see crontab(5)). Cron
then wakes up every minute, examining all stored crontabs,
checking each command to see if it should be run in the
current minute. When executing commands, any output is
mailed to the owner of the crontab (or to the user named
in the MAILTO environment variable in the crontab, if such
exists).

Additionally, cron checks each minute to see if its spool
directory’s modtime (or the modtime on /etc/crontab) has
changed, and if it has, cron will then examine the modtime
on all crontabs and reload those which have changed. Thus
cron need not be restarted whenever a crontab file is mod-
ified. Note that the Crontab(1) command updates the mod-
time of the spool directory whenever it changes a crontab.