CRON(8)

NAME
cron - clock daemon

SYNOPSIS
cron

EXAMPLES

DESCRIPTION

Cron is clock daemon. It is typically started up by including the command /usr/bin/cron in the /etc/rc file. Once started, cron puts itself in the background, so no & is needed. It runs forever, sleeping most of the time. Once a minute it wakes up and examines /usr/lib/crontab to see if there is any work to do. If there is, the work is done. The entries of /usr/lib/crontab contain 6 elements each. Some examples follow:

	Min	Hr	Dat	Mo	Day	Command
	 *	 *	 *	 *	 *	/usr/bin/date >/dev/log   #print date every minute
	 0	 *	 *	 *	 *	/usr/bin/date >/dev/log   #print date on the hour
	30	 4	 *	 *	1-5	/bin/backup /dev/fd1      #do backup Mon-Fri at 0430
	30	19	 *	 *	1,3,5	/etc/backup /dev/fd1      #Mon, Wed, Fri at 1930
	 0	 9	25	12	 *	/usr/bin/sing >/dev/log   #Xmas morning at 0900 only

SEE ALSO
at(1).