.\" Copyright (c) 1980 Regents of the University of California.
.\" All rights reserved. The Berkeley software License Agreement
.\" specifies the terms and conditions for redistribution.
.\" @(#)shutdown.8 6.2 (Berkeley) %G%
shutdown \- close down the system at a given time
time [ warning-message ... ]
provides an automated shutdown procedure which a super-user
nicely when the system is shutting down, saving them from
system administrators, hackers, and gurus, who would otherwise
not bother with niceties.
will bring the system down and
(indicating an immediate shutdown)
or specify a future time in one of two formats:
The first form brings the system down in
and the second brings the system down at the time of day indicated
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
and writing a message there.
If this file exists when a user attempts to log in,
The file is removed just before
message is written in the system log, containing the
time of shutdown, who ran shutdown and the reason.
Then a terminate signal is sent at
to bring the system down to single-user state.
or avoid shutting the system down (respectively).
the system is going down!)
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 not to let anyone log in
Only allows you to kill the system between now and 23:59 if
you use the absolute time for shutdown.