CRON(1M) (Essential Utilities) CRON(1M)
NAME
cron - clock daemon
SYNOPSIS
/etc/cron
DESCRIPTION
cron executes commands at specified dates and times.
Regularly scheduled commands can be specified according to
instructions found in crontab files in the directory
/usr/spool/cron/crontabs. Users can submit their own
crontab file via the crontab(1) command. Commands which are
to be executed only once may be submitted via the at(1)
command.
cron only examines crontab files and at command files during
process initialization and when a file changes via crontab
or at. This reduces the overhead of checking for new or
changed files at regularly scheduled intervals.
Since cron never exits, it should be executed only once.
This is done routinely through /etc/rc2.d/S75cron at system
boot time. /usr/lib/cron/FIFO is used as a lock file to
prevent the execution of more than one cron.
FILES
/usr/lib/cron main cron directory
/usr/lib/cron/FIFO used as a lock file
/usr/lib/cron/log accounting information
/usr/spool/cron spool area
SEE ALSO
at(1), crontab(1), sh(1) in the User's Reference Manual.
DIAGNOSTICS
A history of all actions taken by cron are recorded in
/usr/lib/cron/log.
Page 1 May 1989