SHUTDOWN(8)                  System Administration                 SHUTDOWN(8)




NAME

       shutdown - close down the system at a given time


SYNOPSIS

       shutdown [ - ] [ -hkrn ] time warning-message ...


DESCRIPTION

       Shutdown  provides  an  automated shutdown procedure for super-users to
       nicely notify users when the system is shutting down, saving them  from
       system  administrators,  hackers,  and  gurus,  who would otherwise not
       bother with such niceties.

       Available friendlinesses:

              h      The system is halted at the specified time when  shutdown
                     execs halt(8).

              k      Kick every body off.  The k option does not actually halt
                     the system, but leaves the system multi-user with  logins
                     disabled (for all but super-user).

              n      Prevent the normal sync(2) before stopping.

              r      Shutdown execs reboot(8) at the specified time.

              time   Time  is the time at which shutdown will bring the system
                     down and may be the word  now  (indicating  an  immediate
                     shutdown) or specify a future time in one of two formats:
                     +number, or yymmddhhmm, where the year,  month,  and  day
                     may be defaulted to the current system values.  The first
                     form brings the system down in  number  minutes  and  the
                     second at the absolute time specified.

              warning-message
                     Any  other arguments comprise the warning message that is
                     broadcast to users currently logged into the system.

              -      If - is supplied as an option,  the  warning  message  is
                     read from the standard input.

       At  intervals,  becoming  more  frequent  as  apocalypse approaches and
       starting at ten hours before shutdown, warning messages  are  displayed
       on the terminals of all users logged in.  Five minutes before shutdown,
       or immediately if shutdown is in less than 5 minutes, logins  are  dis-
       abled  by  creating /etc/nologin and copying the warning message there.
       If this file exists when a user attempts to log in, login(1) prints its
       contents and exits.  The file is removed just before shutdown exits.

       At shutdown time a message is written in the system log, containing the
       time of shutdown, who initiated the shutdown and the reason.  A  termi-
       nate  signal  is  then sent to init to bring the system down to single-
       user state (depending on above options).  The time of the shutdown  and
       the  warning  message  are placed in /etc/nologin and should be used to
       inform the users about when the system will be back up and  why  it  is
       going down (or anything else).


FILES

       /etc/nologin
              tells login not to let anyone log in


SEE ALSO

       login(1), wall(1), halt(8), reboot(8)


BACKWARD COMPATIBILITY

       The  hours  and minutes in the second time format may be separated by a
       colon ('':'') for backward compatibility.


HISTORY

       The shutdown command appeared in 4.0BSD.



GNO                             4 October 1997                     SHUTDOWN(8)

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