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.Dd August 4, 2024 29.Dt SHUTDOWN 8 30.Os 31.Sh NAME 32.Nm shutdown , 33.Nm poweroff 34.Nd "close down the system at a given time" 35.Sh SYNOPSIS 36.Nm 37.Op Fl 38.Oo 39.Fl c | Fl f | Fl h | Fl p | 40.Fl r | Fl k 41.Oc 42.Oo 43.Fl o 44.Op Fl n 45.Oc 46.Op Fl q 47.Ar time 48.Op Ar warning-message ... 49.Nm poweroff 50.Sh DESCRIPTION 51The 52.Nm 53utility provides an automated shutdown procedure for super-users 54to nicely notify users when the system is shutting down, 55saving them from system administrators, hackers, and gurus, who 56would otherwise not bother with such niceties. 57In order to use the 58.Nm 59command, the user must have root privileges or be a member of the 60operator group. 61.Pp 62The following options are available: 63.Bl -tag -width indent 64.It Fl c 65The system is power cycled (power turned off and then back on) 66at the specified time. 67If the hardware doesn't support power cycle, the system will be 68rebooted. 69At the present time, only systems with BMC supported by the 70.Xr ipmi 4 71driver that implement this functionality support this flag. 72The amount of time the system is off is dependent on the device 73that implements this feature. 74.It Fl f 75The 76.Nm 77command ignores the presence of the 78.Pa /var/run/noshutdown 79file. 80.It Fl h 81The system is halted at the specified 82.Ar time . 83.It Fl p 84The system is halted and the power is turned off 85(hardware support required, otherwise the system is halted) 86at the specified 87.Ar time . 88.It Fl r 89The system is rebooted at the specified 90.Ar time . 91.It Fl k 92Kick everybody off. 93The 94.Fl k 95option 96does not actually halt the system, but leaves the 97system multi-user with logins disabled (for all but super-user). 98.It Fl o 99If one of the 100.Fl c , 101.Fl h , 102.Fl p 103or 104.Fl r 105options are specified, 106.Nm 107will execute 108.Xr halt 8 109or 110.Xr reboot 8 111instead of sending a signal to 112.Xr init 8 . 113.It Fl n 114If the 115.Fl o 116option is specified, prevent the file system cache from being flushed by passing 117.Fl n 118to 119.Xr halt 8 120or 121.Xr reboot 8 . 122This option should probably not be used. 123.It Fl q 124Shut down quietly. 125Suppress the warning message to all logged in users about system shutdown. 126It is an error to supply a 127.Ar warning-message 128when warnings are suppressed. 129.It Ar time 130.Ar Time 131is the time at which 132.Nm 133will bring the system down and 134may be the case-insensitive word 135.Ar now 136(indicating an immediate shutdown) or 137a future time in one of two formats: 138.Ar +number , 139or 140.Ar yymmddhhmm , 141where the year, month, and day may be defaulted 142to the current system values. 143The first form brings the system down in 144.Ar number 145minutes and the second at the absolute time specified. 146.Ar +number 147may be specified in units other than minutes by appending the corresponding 148suffix: 149.Dq Li s , 150.Dq Li sec , 151.Dq Li m , 152.Dq Li min , 153.Dq Li h , 154.Dq Li hour . 155.Pp 156If an absolute time is specified, but not a date, 157and that time today has already passed, 158.Nm 159will assume that the same time tomorrow was meant. 160(If a complete date is specified which has already passed, 161.Nm 162will print an error and exit without shutting the system down.) 163.It Ar warning-message 164Any other arguments comprise the warning message that is broadcast 165to users currently logged into the system. 166.It Fl 167If 168.Sq Fl 169is supplied as an option, the warning message is read from the standard 170input. 171.El 172.Pp 173At intervals, becoming more frequent as apocalypse approaches 174and starting at ten hours before shutdown, warning messages are displayed 175on the terminals of all users logged in. 176Five minutes before 177shutdown, or immediately if shutdown is in less than 5 minutes, 178logins are disabled by creating 179.Pa /var/run/nologin 180and copying the 181warning message there. 182If this file exists when a user attempts to 183log in, 184.Xr login 1 185prints its contents and exits. 186The file is 187removed just before 188.Nm 189exits. 190.Pp 191At shutdown time a message is written to the system log, containing the 192time of shutdown, the person who initiated the shutdown and the reason. 193The corresponding signal is then sent to 194.Xr init 8 195to respectively halt, reboot or bring the system down to single-user state 196(depending on the above options). 197The time of the shutdown and the warning message 198are placed in 199.Pa /var/run/nologin 200and should be used to 201inform the users about when the system will be back up 202and why it is going down (or anything else). 203.Pp 204A scheduled shutdown can be canceled by killing the 205.Nm 206process (a 207.Dv SIGTERM 208should suffice). 209The 210.Pa /var/run/nologin 211file that 212.Nm 213created will be removed automatically. 214.Pp 215If the 216.Pa /var/run/noshutdown 217file is present, 218.Nm 219exits without executing any action on the system. 220.Pp 221When run without options, the 222.Nm 223utility will place the system into single user mode at the 224.Ar time 225specified. 226.Pp 227Calling 228.Dq Nm poweroff 229is equivalent to running: 230.Bd -literal -offset indent 231shutdown -p now 232.Ed 233.Sh FILES 234.Bl -tag -width /var/run/noshutdown -compact 235.It Pa /var/run/nologin 236tells 237.Xr login 1 238not to let anyone log in 239.It Pa /var/run/noshutdown 240prevents 241.Nm 242from initiating an action on the system. 243Can be overridden with the 244.Fl f 245option. 246.El 247.Sh EXAMPLES 248Reboot the system in 30 minutes and display a warning message on the terminals 249of all users currently logged in: 250.Pp 251.Dl # shutdown -r +30 \&"System will reboot\&" 252.Sh COMPATIBILITY 253The hours and minutes in the second time format may be separated by 254a colon (``:'') for backward compatibility. 255.Sh SEE ALSO 256.Xr kill 1 , 257.Xr login 1 , 258.Xr wall 1 , 259.Xr nologin 5 , 260.Xr halt 8 , 261.Xr init 8 , 262.Xr reboot 8 263.Sh HISTORY 264A 265.Nm 266command was originally written by Ian Johnstone for UNSW's modified 267.At "6th Edn" . 268It was modified and then incorporated in 269.Bx 4.1 . 270