ultrix man page for shutdown

shutdown(8)						      System Manager's Manual						       shutdown(8)

Name
       shutdown - close down the system at a given time

Syntax
       /etc/shutdown [ -k ] [ -r ] [ -h ] [ -o ] time [ warning-message ... ]

Description
       The command provides an automated shutdown procedure that a superuser can use to notify users when the system is shutting down.

       The  time is the time at which will bring the system down.  It may be the word `now', indicating an immediate shutdown, or specify a future
       time in one of two formats: + number or hour : min.  The first form brings the system down in number minutes.  The second brings the system
       down at the time of day indicated, using a 24-hour clock format.

       At intervals which get shorter as shutdown nears, warning messages are displayed at the terminals of all users on the system.  Warning mes-
       sages are also sent to users who are logged in to a remote system that has mounted a file system or directory from the local  system  using
       NFS.   Five  minutes  before  shutdown, or immediately if shutdown is timed for less than five minutes, logins are disabled by creating and
       writing a message there.  If this file exists when a user attempts to log in, prints its contents and exits.   The  file  is  removed  just
       before exits.

       At  shutdown  time, a message is written in the file This message contains the time of shutdown, who ran shutdown, and the reason.  Then, a
       terminate signal is sent at to bring the system to single-user state.

       If the or options are used, then executes or avoids shutting the system down (respectively).  The option is for use by only.  It  indicates
       to that it is being called by and not to return to the user.

       You should place the time of the shutdown and the warning message in Use the message to inform the users about when the system will be back
       up and why it is going down.

Restrictions
       You can kill the system only between now and 23:59, if you use the absolute time for shutdown.

Files
       Tells login not to let anyone log in

       Log file for successful shutdowns

See Also
       login(1), wall(1), halt(8), opser(8), reboot(8), rwalld(8c)

																       shutdown(8)