SHUTDOWN(8)SHUTDOWN(8)NAMEshutdown - close down the system at a given time
SYNOPSIS
/usr/etc/shutdown [ -k ] [ -r ] [ -h ] [ -n ] [ -p ] time [ warning-
message ... ]
DESCRIPTION
Shutdown provides an automated shutdown procedure which a super-user
can use to notify users nicely when the system is shutting down, saving
them from system administrators, hackers, and gurus, who would
otherwise not bother with niceties.
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 and hour:min. The first form
brings the system down in number minutes and the second brings the
system down at the time of day indicated (as a 24-hour clock).
At intervals which get closer together as apocalypse approaches,
warning messages are displayed at the terminals of all users on the
system. Five minutes before shutdown, or immediately if shutdown is in
less than 5 minutes, logins are disabled by creating /etc/nologin and
writing a 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 ran shutdown and the reason. Then a terminate
signal is sent to init to bring the system down to single-user state.
Alternatively, if -r, -h, or -k was used, then shutdown will exec
reboot(8), halt(8), or avoid shutting the system down (respectively).
(If it isn't obvious, -k is to make people think the system is going
down!)
The -n option prevents the normal sync(2) before stopping. The -p
option causes the machine to be powered down if the -h option is also
specified.
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).
FILES
/etc/nologin tells login not to let anyone log in
SEE ALSOlogin(1), reboot(8)BUGS
Only allows you to kill the system between now and 23:59 if you use the
absolute time for shutdown.
4th Berkeley Distribution July 7, 1988 SHUTDOWN(8)