Updated: 2022/Sep/29

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

     shutdown - close down the system at a given time

     shutdown [-Ddfhknprvxz] [-b bootstr] 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) to
              request a kernel core dump.  If neither 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, using halt(8).

     -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, using
              poweroff(8).  If the powerdown fails, or the system does not
              support software powerdown, the system will simply halt instead.

     -r       The system is rebooted at the specified time, using reboot(8).

     -v       To enable verbose messages on the console, pass -v to reboot(8)
              or halt(8).

     -x       To enable debugging messages on the console, pass -x to
              reboot(8) or halt(8).

     -z       To silence some shutdown messages on the console, pass -z to
              reboot(8) or halt(8).

     -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 are two digit decimal values, which may be
              defaulted to the current system values.  The two digit (decimal,
              even with a leading zero) minute field is required in this form.
              The first form brings the system down number minutes from the
              current time; the second brings the system down at the absolute
              time specified.  If the century is not specified, but the year
              is, the century defaults to 2000 (cc==20, the 21st century) for
              years between 20 and 99, or 2100 for years between 0 and 19.  A
              leading zero in the "yy" value (as with all the others) is not

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

     -        If - is supplied as the only argument after the time, 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 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
     message 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,
     shutdown runs halt(8) or reboot(8), or sends a terminate signal to
     init(8) to bring the system down to single-user mode, depending on the
     choice of options.

     The time of the shutdown and the warning message are placed in
     /etc/nologin and should be used to tell the users why the system is going
     down, when it will be back up, and to share any other pertinent

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

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

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

     A shutdown command was originally written by Ian Johnstone for UNSW's
     modified Version 6 AT&T UNIX, modified, and then incorporated in 4.1BSD.

NetBSD 9.99                      July 1, 2022                      NetBSD 9.99