shutdown(ADM)                   19 June 1992                   shutdown(ADM)


 Name

    shutdown - terminate all processing

 Syntax

    /etc/shutdown [ -y ] [ -g[hh:]mm ] [ -i[0156sS] ]
    [ -f "mesg" ] [ -f file ] [ su ]

 Description

    The primary function of shutdown is to terminate all currently running
    processes in an orderly and cautious manner.  shutdown goes through the
    following steps:

    1.  All users logged on the system are notified to log off the system by
        a broadcast message.

    2.  /etc/init is called to perform the actual shutdown.

    Only the super user can execute the shutdown command.

    The options are as follows:

    -y         Runs the command silently.  If this option is not specified,
               shutdown will prompt for confirmation to shut down the system.

    -g[hh:]mm  Specifies the number of hours and minutes before shutdown
               (maximum:  72 hours).  1 minute is the default.  (To shut down
               the system immediately without a grace period, use
               /etc/haltsys or /etc/reboot.  Note that these commands should
               not be used if NFS, TCP/IP or certain other services are run-
               ning.)

    -i[0156sS] Specifies the init level to bring the system to (see init(M)).
               By default, the system is brought to level 0.

    -f ``mesg''
               mesg is a message enclosed in double quotes (" ") to be sent
               to all terminals warning of the imminent shutdown during the
               grace period.

    -f file    Similar to the -f mesg option, but file is the pathname for a
               file containing the message.

    The optional su argument lets the user go single-user without completely
    shutting down the system.  (This option is identical to -i1 and is
    present for backwards compatibility with XENIX).  Broadcast messages,
    whether default or defined, are displayed at regular intervals during the
    grace period.  The closer the shutdown time, the more frequent the mes-
    sage:

    _________________________________________________________________________
    Time left until shutdown              Frequency of message
    _________________________________________________________________________
    Greater than 1 hour                   Every hour
    Greater than 15 minutes               Every 15 minutes
    Less than 15 minutes                  Every minute

    In general, if no options are specified, shutdown behaves as follows:

    1.  Prompt for confirmation

    2.  60-second grace period

    3.  Bring the system to init level 0

    4.  Broadcast default message prior to shutdown.

 See also

    boot(HW), wall(ADM)

 Diagnostics

    The most common error diagnostic that will occur is device busy.  This
    diagnostic appears when a particular filesystem could not be unmounted.
    See umount(ADM).

 Notes

    Once shutdown has been invoked, it must be allowed to run to completion
    and must not be interrupted by pressing BREAK or DEL.

    shutdown does not work when executed from within a shell layer.

    shutdown locks the hard disk heads.

 Credit

    shutdown was developed at the University of California, Berkeley, and is
    used with permission.