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.\" 31.Dd September 29, 2016 32.Dt SHUTDOWN 8 33.Os 34.Sh NAME 35.Nm shutdown , 36.Nm poweroff 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.Nm poweroff 52.Sh DESCRIPTION 53The 54.Nm 55utility provides an automated shutdown procedure for super-users 56to nicely notify users when the system is shutting down, 57saving them from system administrators, hackers, and gurus, who 58would otherwise not bother with such niceties. 59.Pp 60The following options are available: 61.Bl -tag -width indent 62.It Fl h 63The system is halted at the specified 64.Ar time . 65.It Fl p 66The system is halted and the power is turned off 67(hardware support required) 68at the specified 69.Ar time . 70.It Fl r 71The system is rebooted at the specified 72.Ar time . 73.It Fl k 74Kick everybody off. 75The 76.Fl k 77option 78does not actually halt the system, but leaves the 79system multi-user with logins disabled (for all but super-user). 80.It Fl o 81If one of the 82.Fl h , 83.Fl p 84or 85.Fl r 86is specified, 87.Nm 88will execute 89.Xr halt 8 90or 91.Xr reboot 8 92instead of sending signal to 93.Xr init 8 . 94.It Fl n 95If the 96.Fl o 97is specified, prevent the file system cache from being flushed by passing 98.Fl n 99option to 100.Xr halt 8 101or 102.Xr reboot 8 . 103This option should probably not be used. 104.It Ar time 105.Ar Time 106is the time at which 107.Nm 108will bring the system down and 109may be the word 110.Ar now 111(indicating an immediate shutdown) or 112specify a future time in one of two formats: 113.Ar +number , 114or 115.Ar yymmddhhmm , 116where the year, month, and day may be defaulted 117to the current system values. The first form brings the system down in 118.Ar number 119minutes and the second at the absolute time specified. 120.It Ar warning-message 121Any other arguments comprise the warning message that is broadcast 122to users currently logged into the system. 123.It Fl 124If 125.Sq Fl 126is supplied as an option, the warning message is read from the standard 127input. 128.El 129.Pp 130At intervals, becoming more frequent as apocalypse approaches 131and starting at ten hours before shutdown, warning messages are displayed 132on the terminals of all users logged in. Five minutes before 133shutdown, or immediately if shutdown is in less than 5 minutes, 134logins are disabled by creating 135.Pa /var/run/nologin 136and copying the 137warning message there. If this file exists when a user attempts to 138log in, 139.Xr login 1 140prints its contents and exits. The file is 141removed just before 142.Nm 143exits. 144.Pp 145At shutdown time a message is written to the system log, containing the 146time of shutdown, the person who initiated the shutdown and the reason. 147Corresponding signal is then sent to 148.Xr init 8 149to respectively halt, reboot or bring the system down to single-user state 150(depending on the above options). 151The time of the shutdown and the warning message 152are placed in 153.Pa /var/run/nologin 154and should be used to 155inform the users about when the system will be back up 156and why it is going down (or anything else). 157.Pp 158A scheduled shutdown can be canceled by killing the 159.Nm 160process (a 161.Dv SIGTERM 162should suffice). 163The 164.Pa /var/run/nologin 165file that 166.Nm 167created will be removed automatically. 168.Pp 169Calling 170.Dq Nm poweroff 171is equivalent to running: 172.Bd -literal -offset indent 173shutdown -p now 174.Ed 175.Sh FILES 176.Bl -tag -width /var/run/nologin -compact 177.It Pa /var/run/nologin 178tells login not to let anyone log in 179.El 180.Sh BACKWARD COMPATIBILITY 181The hours and minutes in the second time format may be separated by 182a colon (``:'') for backward compatibility. 183.Sh SEE ALSO 184.Xr kill 1 , 185.Xr login 1 , 186.Xr wall 1 , 187.Xr nologin 5 , 188.Xr halt 8 , 189.Xr init 8 , 190.Xr reboot 8 191.Sh HISTORY 192A 193.Nm 194command was originally written by Ian Johnstone for UNSW's modified 195.At v6 . 196It was modified and then incorporated in 197.Bx 4.1 . 198