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.\" $FreeBSD$ 30.\" 31.Dd September 21, 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 86options are specified, 87.Nm 88will execute 89.Xr halt 8 90or 91.Xr reboot 8 92instead of sending a signal to 93.Xr init 8 . 94.It Fl n 95If the 96.Fl o 97option is specified, prevent the file system cache from being flushed by passing 98.Fl n 99to 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 case-insensitive word 110.Ar now 111(indicating an immediate shutdown) or 112a 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. 118The first form brings the system down in 119.Ar number 120minutes and the second at the absolute time specified. 121.Ar +number 122may be specified in units other than minutes by appending the corresponding 123suffix: 124.Dq Li s , 125.Dq Li sec , 126.Dq Li m , 127.Dq Li min . 128.Dq Li h , 129.Dq Li hour . 130.It Ar warning-message 131Any other arguments comprise the warning message that is broadcast 132to users currently logged into the system. 133.It Fl 134If 135.Sq Fl 136is supplied as an option, the warning message is read from the standard 137input. 138.El 139.Pp 140At intervals, becoming more frequent as apocalypse approaches 141and starting at ten hours before shutdown, warning messages are displayed 142on the terminals of all users logged in. 143Five minutes before 144shutdown, or immediately if shutdown is in less than 5 minutes, 145logins are disabled by creating 146.Pa /var/run/nologin 147and copying the 148warning message there. 149If this file exists when a user attempts to 150log in, 151.Xr login 1 152prints its contents and exits. 153The file is 154removed just before 155.Nm 156exits. 157.Pp 158At shutdown time a message is written to the system log, containing the 159time of shutdown, the person who initiated the shutdown and the reason. 160The corresponding signal is then sent to 161.Xr init 8 162to respectively halt, reboot or bring the system down to single-user state 163(depending on the above options). 164The time of the shutdown and the warning message 165are placed in 166.Pa /var/run/nologin 167and should be used to 168inform the users about when the system will be back up 169and why it is going down (or anything else). 170.Pp 171A scheduled shutdown can be canceled by killing the 172.Nm 173process (a 174.Dv SIGTERM 175should suffice). 176The 177.Pa /var/run/nologin 178file that 179.Nm 180created will be removed automatically. 181.Pp 182When run without options, the 183.Nm 184utility will place the system into single user mode at the 185.Ar time 186specified. 187.Pp 188Calling 189.Dq Nm poweroff 190is equivalent to running: 191.Bd -literal -offset indent 192shutdown -p now 193.Ed 194.Sh FILES 195.Bl -tag -width /var/run/nologin -compact 196.It Pa /var/run/nologin 197tells 198.Xr login 1 199not to let anyone log in 200.El 201.Sh EXAMPLES 202Reboot the system in 30 minutes and display a warning message on the terminals 203of all users currently logged in: 204.Pp 205.Dl # shutdown -r +30 \&"System will reboot\&" 206.Sh COMPATIBILITY 207The hours and minutes in the second time format may be separated by 208a colon (``:'') for backward compatibility. 209.Sh SEE ALSO 210.Xr kill 1 , 211.Xr login 1 , 212.Xr wall 1 , 213.Xr nologin 5 , 214.Xr halt 8 , 215.Xr init 8 , 216.Xr reboot 8 217.Sh HISTORY 218A 219.Nm 220command was originally written by Ian Johnstone for UNSW's modified 221.At "6th Edn" . 222It was modified and then incorporated in 223.Bx 4.1 . 224