1.\" Copyright (c) 1988, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)shutdown.8 8.2 (Berkeley) 4/27/95 29.\" $FreeBSD: src/sbin/shutdown/shutdown.8,v 1.12.2.5 2003/02/23 21:17:43 trhodes Exp $ 30.\" $DragonFly: src/sbin/shutdown/shutdown.8,v 1.3 2006/02/17 19:33:33 swildner Exp $ 31.\" 32.Dd December 11, 1998 33.Dt SHUTDOWN 8 34.Os 35.Sh NAME 36.Nm shutdown 37.Nd "close down the system at a given time" 38.Sh SYNOPSIS 39.Nm 40.Op Fl 41.Oo 42.Fl h | Fl p | 43.Fl r | Fl k 44.Oc 45.Oo 46.Fl o 47.Op Fl n 48.Oc 49.Ar time 50.Op Ar warning-message ... 51.Sh DESCRIPTION 52The 53.Nm 54utility provides an automated shutdown procedure for super-users 55to nicely notify users when the system is shutting down, 56saving them from system administrators, hackers, and gurus, who 57would otherwise not bother with such niceties. 58.Pp 59The following options are available: 60.Bl -tag -width indent 61.It Fl h 62The system is halted at the specified 63.Ar time . 64.It Fl p 65The system is halted and the power is turned off 66(hardware support required) 67at the specified 68.Ar time . 69.It Fl r 70The system is rebooted at the specified 71.Ar time . 72.It Fl k 73Kick everybody off. 74The 75.Fl k 76option 77does not actually halt the system, but leaves the 78system multi-user with logins disabled (for all but super-user). 79.It Fl o 80If one of the 81.Fl h , 82.Fl p 83or 84.Fl r 85is specified, 86.Nm 87will execute 88.Xr halt 8 89or 90.Xr reboot 8 91instead of sending signal to 92.Xr init 8 . 93.It Fl n 94If the 95.Fl o 96is specified, prevent the file system cache from being flushed by passing 97.Fl n 98option to 99.Xr halt 8 100or 101.Xr reboot 8 . 102This option should probably not be used. 103.It Ar time 104.Ar Time 105is the time at which 106.Nm 107will bring the system down and 108may be the word 109.Ar now 110(indicating an immediate shutdown) or 111specify a future time in one of two formats: 112.Ar +number , 113or 114.Ar yymmddhhmm , 115where the year, month, and day may be defaulted 116to the current system values. The first form brings the system down in 117.Ar number 118minutes and the second at the absolute time specified. 119.It Ar warning-message 120Any other arguments comprise the warning message that is broadcast 121to users currently logged into the system. 122.It Fl 123If 124.Sq Fl 125is supplied as an option, the warning message is read from the standard 126input. 127.El 128.Pp 129At intervals, becoming more frequent as apocalypse approaches 130and starting at ten hours before shutdown, warning messages are displayed 131on the terminals of all users logged in. Five minutes before 132shutdown, or immediately if shutdown is in less than 5 minutes, 133logins are disabled by creating 134.Pa /var/run/nologin 135and copying the 136warning message there. If this file exists when a user attempts to 137log in, 138.Xr login 1 139prints its contents and exits. The file is 140removed just before 141.Nm 142exits. 143.Pp 144At shutdown time a message is written to the system log, containing the 145time of shutdown, the person who initiated the shutdown and the reason. 146Corresponding signal is then sent to 147.Xr init 8 148to respectively halt, reboot or bring the system down to single-user state 149(depending on the above options). 150The time of the shutdown and the warning message 151are placed in 152.Pa /var/run/nologin 153and should be used to 154inform the users about when the system will be back up 155and why it is going down (or anything else). 156.Pp 157A scheduled shutdown can be canceled by killing the 158.Nm 159process (a 160.Dv SIGTERM 161should suffice). 162The 163.Pa /var/run/nologin 164file that 165.Nm 166created will be removed automatically. 167.Sh FILES 168.Bl -tag -width /var/run/nologin -compact 169.It Pa /var/run/nologin 170tells login not to let anyone log in 171.El 172.Sh BACKWARD COMPATIBILITY 173The hours and minutes in the second time format may be separated by 174a colon (``:'') for backward compatibility. 175.Sh SEE ALSO 176.Xr kill 1 , 177.Xr login 1 , 178.Xr wall 1 , 179.Xr nologin 5 , 180.Xr halt 8 , 181.Xr init 8 , 182.Xr reboot 8 183.Sh HISTORY 184The 185.Nm 186utility appeared in 187.Bx 4.0 . 188