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SHUTDOWN(8)               BSD System Manager's Manual              SHUTDOWN(8)

     shutdown -- close down the system at a given time

     shutdown [-b bootstr] [-Ddfhknpr] time [message ... | -]

     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:

     -b bootstr
              The given bootstr is passed to reboot(8) for the benefit of
              those systems that can pass boot arguments to the firmware.
              Currently, this only affects sun3 and sparc machines.

     -d       shutdown will pass the -d flag to reboot(8) or halt(8).  If nei-
              ther the -h or -r flags are specified, then -d also implies -r.

     -f       shutdown arranges, in the manner of fastboot(8), for the file
              systems not to be checked on reboot.

     -h       The system is halted at the specified time when shutdown execs

     -k       Kick everybody 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.

     -p       The system is powered down at the specified time when shutdown
              execs halt(8).  If the powerdown fails, or the system does not
              support software powerdown, the system will simply halt.

     -r       The system is rebooted at the specified time when shutdown execs

     -D       Prevents shutdown from detaching from the tty with fork(2)/

     time     Time is the time at which shutdown will bring the system down
              and may be the word now or a future time in one of two formats:
              +number, or [[[[[cc]yy]mm]dd]hh]mm, where the century, year,
              month, day, and hour may be defaulted to the current system val-
              ues.  The first form brings the system down number minutes from
              the current time; the second brings the system down at the abso-
              lute time specified.  If the century is not specified, it
              defaults to 1900 for years between 69 and 99, or 2000 for years
              between 0 and 68.  A leading zero in the ``yy'' value is not

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

     -        If - is supplied as the only argument after the time, the warn-
              ing message is read from the standard input.

     At intervals, becoming more frequent as apocalypse approaches and start-
     ing at ten hours before shutdown, warning messages are displayed on the
     terminals of all users logged in.  Five minutes before shutdown, or imme-
     diately if shutdown is in less than 5 minutes, logins are disabled 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.  Next a mes-
     sage is printed announcing the start of the system shutdown hooks.  Then
     the shutdown hooks in /etc/rc.shutdown are run.  And a message is printed
     indicating that they have completed.  After a short delay a terminate
     signal is then sent to init(8) 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).

     /etc/nologin      tells login(1) not to let anyone log in
     /fastboot         tells rc(8) not to run fsck when rebooting
     /etc/rc.shutdown  System shutdown commands

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

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

     The shutdown command appeared in 4.0BSD.

BSD                            October 18, 2002                            BSD