cron(1M)                                                              cron(1M)



NAME
     cron - clock daemon

SYNOPSIS
     cron [ -j jobs ] [ nofork ]

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 /var/spool/cron/crontabs.  Users can submit their
     own crontab file via the crontab(1) command.  Commands that are to be
     executed only once can be submitted using the at(1) command.

     The following options are supported:

     -j jobs   Specify the maximum number of jobs (MAXRUN) that cron can
               simultaneously run.  The default value is 25.  The maximum
               allowed value is 250.

     nofork    If this option is supplied, cron runs in the foreground.

     cron examines crontab files and at command files only 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.
     /etc/cron.d/FIFO is used as a lock file to prevent the execution of more
     than one cron and is also used by the crontab command for notification of
     changes to the crontab files.

     If MAXRUN jobs are running and another is scheduled, cron does not run
     the new job.  A message is logged via syslog(3C).

     cron attempts to handle changes to the system date correctly, either
     forward or backward.  There may be some delay for jobs scheduled during
     the interval on large forward-time changes.

FILES
     /etc/cron.d                main cron directory
     /etc/cron.d/FIFO           used as a lock file against multiple copies
                                running and also for notification of new or
                                changed crontab files
     /var/cron/log              accounting information
     /var/spool/cron            spool area
     /etc/config/cron.options   site-dependent options

SIGNALS
     A SIGHUP signal can be sent to cron to cause it to reexamine all the
     crontab and configuration files.  A message is logged for this event.
     The SIGTERM signal should be used to shut cron down cleanly.



                                                                        Page 1

cron(1M)                                                              cron(1M)



SEE ALSO
     at(1), crontab(1), sh(1).

DIAGNOSTICS
     A history of all actions taken by cron is recorded in /var/cron/log.


















































                                                                        Page 2