man : shutdown(8)
SHUTDOWN(8) OpenBSD System Manager's Manual SHUTDOWN(8)
shutdown - close down the system at a given time
shutdown [-] [-dfhknpr] time [warning-message ...]
shutdown provides an automated shutdown procedure for superusers 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. When the shutdown command is issued without options
the system is placed in single user mode at the indicated time after
shutting down all system services.
The options are as follows:
-d When used with -h or -r causes system to perform a dump. This
option is useful for debugging system dump procedures or
capturing the state of a corrupted or misbehaving system. See
savecore(8) for information on how to recover this dump.
-f Create the file /fastboot so that the file systems will not be
checked by fsck(8) during the next boot. (See rc(8)).
-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 superuser).
-n When used with -h or -r prevents the normal sync(2) before
stopping the system.
-p The -p flag is passed on to halt(8), causing machines which
support automatic power down to do so after halting.
-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.
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 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. A terminate
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
You can cancel a scheduled shutdown with the kill(1) command by killing
the shutdown process.
/etc/nologin tells login not to let anyone log in
/etc/rc.shutdown run by rc(8) before the system is shutdown
/fastboot tells rc(8) not to run fsck(8) during the next boot
kill(1), login(1), wall(1), halt(8), rc.shutdown(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.
OpenBSD 4.9 November 19, 2007 OpenBSD 4.9