CRON(8)CRON(8)NAME
cron - clock daemon
SYNOPSIS
/usr/etc/cron
DESCRIPTION
Cron executes commands at specified dates and times according to the
instructions in the files /private/etc/crontab and
/private/etc/crontab.local. None, either one, or both of these files
may be present. Since cron never exits, it should only be executed
once. This is best done by running cron from the initialization
process through the file /etc/rc; see init(8).
The crontab files consist of lines of seven fields each. The fields
are separated by spaces or tabs. The first five are integer patterns
to specify:
· minute (0-59)
· hour (0-23)
· day of the month (1-31)
· month of the year (1-12)
· day of the week (1-7 with 1 = Monday)
Each of these patterns may contain:
· a number in the range above
· two numbers separated by a minus meaning a range inclusive
· a list of numbers separated by commas meaning any of the numbers
· an asterisk meaning all legal values
The sixth field is a user name: the command will be run with that
user's uid and permissions. The seventh field consists of all the text
on a line following the sixth field, including spaces and tabs; this
text is treated as a command which is executed by the Shell at the
specified times. A percent character (``%'') in this field is
translated to a new-line character.
Both crontab files are checked by cron every minute, on the minute.
FILES
/private/etc/crontab
/private/etc/crontab.local
/usr/lib/crontab (link to /private/etc/crontab)
/usr/lib/crontab.local (link to /private/etc/crontab.local)
7th Edition May 16, 1986 CRON(8)