.\" Copyright (c) 1988, 1991, 1993 .\" The Regents of the University of California. All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. All advertising materials mentioning features or use of this software .\" must display the following acknowledgement: .\" This product includes software developed by the University of .\" California, Berkeley and its contributors. .\" 4. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" @(#)shutdown.8 8.2 (Berkeley) 4/27/95 .\" $FreeBSD: src/sbin/shutdown/shutdown.8,v 1.21 2002/12/23 16:04:50 ru Exp $ .\" .Dd December 11, 1998 .Dt SHUTDOWN 8 .Os .Sh NAME .Nm shutdown .Nd "close down the system at a given time" .Sh SYNOPSIS .Nm .Op Fl .Oo .Fl h .Op Fl u | .Fl r | Fl k .Oc .Oo .Fl o .Op Fl n .Oc .Ar time .Op Ar warning-message ... .Sh DESCRIPTION The .Nm utility 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. .Pp The following options are available: .Bl -tag -width indent .It Fl h The system is halted at the specified .Ar time . .It Fl r The system is rebooted at the specified .Ar time . .It Fl k Kick everybody off. The .Fl k option does not actually halt the system, but leaves the system multi-user with logins disabled (for all but super-user). .It Fl o If .Fl h or .Fl r is specified, .Nm will execute .Xr halt 8 or .Xr reboot 8 instead of sending signal to .Xr init 8 . .It Fl n If the .Fl o is specified, prevent the file system cache from being flushed by passing .Fl n option to .Xr halt 8 or .Xr reboot 8 . This option should probably not be used. .It Fl u The system is halted up until the point of removing system power, but waits before removing power for 5 minutes so that an external UPS (uninterruptible power supply) can forcibly remove power. This simulates a dirty shutdown to permit a later automatic power on. OS X uses this mode automatically with supported UPSs in emergency shutdowns. .It Ar time .Ar Time is the time at which .Nm will bring the system down and may be the word .Ar now (indicating an immediate shutdown) or specify a future time in one of two formats: .Ar +number , or .Ar yymmddhhmm , where the year, month, and day may be defaulted to the current system values. The first form brings the system down in .Ar number minutes and the second at the absolute time specified. .It Ar warning-message Any other arguments comprise the warning message that is broadcast to users currently logged into the system. .It Fl If .Sq Fl is supplied as an option, the warning message is read from the standard input. .El .Pp 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 .Pa /var/run/nologin and copying the warning message there. If this file exists when a user attempts to log in, .Xr login 1 prints its contents and exits. The file is removed just before .Nm exits. .Pp At shutdown time a message is written to the system log, containing the time of shutdown, the person who initiated the shutdown and the reason. Corresponding signal is then sent to .Xr init 8 to respectively halt, reboot or bring the system down to single-user state (depending on the above options). The time of the shutdown and the warning message are placed in .Pa /var/run/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). .Pp A scheduled shutdown can be canceled by killing the .Nm process (a .Dv SIGTERM should suffice). The .Pa /var/run/nologin file that .Nm created will be removed automatically. .Sh FILES .Bl -tag -width /var/run/nologin -compact .It Pa /var/run/nologin tells login not to let anyone log in .El .Sh SEE ALSO .Xr kill 1 , .Xr login 1 , .Xr wall 1 , .Xr nologin 5 , .Xr halt 8 , .Xr init 8 , .Xr reboot 8 .Sh BACKWARD COMPATIBILITY The hours and minutes in the second time format may be separated by a colon (``:'') for backward compatibility. .Sh HISTORY The .Nm utility appeared in .Bx 4.0 .