shutdown(8) - NetBSD Manual Pages

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


NAME

     shutdown -- close down the system at a given time


SYNOPSIS

     shutdown [-Ddfhknprvxz] [-b bootstr] time [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:

     -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)/
              exit(3).

     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
              optional.

     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.


BEHAVIOR

     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
     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 informa-
     tion.


FILES

     /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


SEE ALSO

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


BACKWARD COMPATIBILITY

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


HISTORY

     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 10.1                      July 1, 2022                      NetBSD 10.1