cron(8)                             CLIX                             cron(8)



  NAME

    cron - Clock daemon

  SYNOPSIS

    /etc/cron

  DESCRIPTION

    The cron command executes commands at specified dates and times.
    Regularly scheduled commands (often called cron jobs) can be specified
    according to instructions found in crontab files in the directory
    /usr/spool/cron/crontabs.  Users can submit their own crontab file with
    the crontab command.  Commands that are to be executed only once may be
    submitted with the at command.

    The cron command examines only crontab files and at command files during
    process initialization and when a file changes with 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
    functionly through /etc/rc2.d/S75cron at system boot time.  The
    /usr/lib/cron/FIFO file is used as a lock to prevent the execution of more
    than one cron daemon.

  EXAMPLES

    The following starts the cron daemon:

    cron

    An error message displays if the cron daemon is already running.

  NOTES

    If the machine time changes, cron corrects its operating times after
    executing once under the new machine time.  This may cause cron jobs to
    run twice after a change to daylight savings time.

  FILES

    /usr/lib/cron        Main cron directory.

    /usr/lib/cron/FIFO   Lock file to prevent multiple cron daemons from
                         running.

    /usr/lib/cron/log    Accounting information.

    /usr/spool/cron      Spool area.



  2/94 - Intergraph Corporation                                              1

  cron(8)                             CLIX                             cron(8)



  EXIT VALUES

    Standard exit values are not valid, but a history of all actions taken by
    cron is recorded in /usr/lib/cron/log.

  RELATED INFORMATION

    Commands:  at(1), crontab(1), sh(1)














































  2                                              Intergraph Corporation - 2/94