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.\" 30.Dd November 7, 2022 31.Dt SHUTDOWN 8 32.Os 33.Sh NAME 34.Nm shutdown , 35.Nm poweroff 36.Nd "close down the system at a given time" 37.Sh SYNOPSIS 38.Nm 39.Op Fl 40.Oo 41.Fl c | Fl h | Fl p | 42.Fl r | Fl k 43.Oc 44.Oo 45.Fl o 46.Op Fl n 47.Oc 48.Ar time 49.Op Ar warning-message ... 50.Nm poweroff 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. 58In order to use the 59.Nm 60command, the user must have root privileges or be a member of the 61operator group. 62.Pp 63The following options are available: 64.Bl -tag -width indent 65.It Fl c 66The system is power cycled (power turned off and then back on) 67at the specified time. 68If the hardware doesn't support power cycle, the system will be 69rebooted. 70At the present time, only systems with BMC supported by the 71.Xr ipmi 4 72driver that implement this functionality support this flag. 73The amount of time the system is off is dependent on the device 74that implements this feature. 75.It Fl h 76The system is halted at the specified 77.Ar time . 78.It Fl p 79The system is halted and the power is turned off 80(hardware support required, otherwise the system is halted) 81at the specified 82.Ar time . 83.It Fl r 84The system is rebooted at the specified 85.Ar time . 86.It Fl k 87Kick everybody off. 88The 89.Fl k 90option 91does not actually halt the system, but leaves the 92system multi-user with logins disabled (for all but super-user). 93.It Fl o 94If one of the 95.Fl c , 96.Fl h , 97.Fl p 98or 99.Fl r 100options are specified, 101.Nm 102will execute 103.Xr halt 8 104or 105.Xr reboot 8 106instead of sending a signal to 107.Xr init 8 . 108.It Fl n 109If the 110.Fl o 111option is specified, prevent the file system cache from being flushed by passing 112.Fl n 113to 114.Xr halt 8 115or 116.Xr reboot 8 . 117This option should probably not be used. 118.It Ar time 119.Ar Time 120is the time at which 121.Nm 122will bring the system down and 123may be the case-insensitive word 124.Ar now 125(indicating an immediate shutdown) or 126a future time in one of two formats: 127.Ar +number , 128or 129.Ar yymmddhhmm , 130where the year, month, and day may be defaulted 131to the current system values. 132The first form brings the system down in 133.Ar number 134minutes and the second at the absolute time specified. 135.Ar +number 136may be specified in units other than minutes by appending the corresponding 137suffix: 138.Dq Li s , 139.Dq Li sec , 140.Dq Li m , 141.Dq Li min , 142.Dq Li h , 143.Dq Li hour . 144.Pp 145If an absolute time is specified, but not a date, 146and that time today has already passed, 147.Nm 148will assume that the same time tomorrow was meant. 149(If a complete date is specified which has already passed, 150.Nm 151will print an error and exit without shutting the system down.) 152.It Ar warning-message 153Any other arguments comprise the warning message that is broadcast 154to users currently logged into the system. 155.It Fl 156If 157.Sq Fl 158is supplied as an option, the warning message is read from the standard 159input. 160.El 161.Pp 162At intervals, becoming more frequent as apocalypse approaches 163and starting at ten hours before shutdown, warning messages are displayed 164on the terminals of all users logged in. 165Five minutes before 166shutdown, or immediately if shutdown is in less than 5 minutes, 167logins are disabled by creating 168.Pa /var/run/nologin 169and copying the 170warning message there. 171If this file exists when a user attempts to 172log in, 173.Xr login 1 174prints its contents and exits. 175The file is 176removed just before 177.Nm 178exits. 179.Pp 180At shutdown time a message is written to the system log, containing the 181time of shutdown, the person who initiated the shutdown and the reason. 182The corresponding signal is then sent to 183.Xr init 8 184to respectively halt, reboot or bring the system down to single-user state 185(depending on the above options). 186The time of the shutdown and the warning message 187are placed in 188.Pa /var/run/nologin 189and should be used to 190inform the users about when the system will be back up 191and why it is going down (or anything else). 192.Pp 193A scheduled shutdown can be canceled by killing the 194.Nm 195process (a 196.Dv SIGTERM 197should suffice). 198The 199.Pa /var/run/nologin 200file that 201.Nm 202created will be removed automatically. 203.Pp 204When run without options, the 205.Nm 206utility will place the system into single user mode at the 207.Ar time 208specified. 209.Pp 210Calling 211.Dq Nm poweroff 212is equivalent to running: 213.Bd -literal -offset indent 214shutdown -p now 215.Ed 216.Sh FILES 217.Bl -tag -width /var/run/nologin -compact 218.It Pa /var/run/nologin 219tells 220.Xr login 1 221not to let anyone log in 222.El 223.Sh EXAMPLES 224Reboot the system in 30 minutes and display a warning message on the terminals 225of all users currently logged in: 226.Pp 227.Dl # shutdown -r +30 \&"System will reboot\&" 228.Sh COMPATIBILITY 229The hours and minutes in the second time format may be separated by 230a colon (``:'') for backward compatibility. 231.Sh SEE ALSO 232.Xr kill 1 , 233.Xr login 1 , 234.Xr wall 1 , 235.Xr nologin 5 , 236.Xr halt 8 , 237.Xr init 8 , 238.Xr reboot 8 239.Sh HISTORY 240A 241.Nm 242command was originally written by Ian Johnstone for UNSW's modified 243.At "6th Edn" . 244It was modified and then incorporated in 245.Bx 4.1 . 246