SHUTDOWN(8) FreeBSD System Manager's Manual SHUTDOWN(8)
NAME
shutdown, poweroff - close down the system at a given time
SYNOPSIS
shutdown [-] [-c | -f | -h | -p | -r | -k] [-o [-n]] [-q] time
[warning-message ...]
poweroff
DESCRIPTION
The shutdown utility provides an automated shutdown procedure for super-
users to nicely notify users when the system is shutting down, saving
them from system administrators, hackers, and gurus, who would otherwise
not bother with such niceties. In order to use the shutdown command, the
user must have root privileges or be a member of the operator group.
The following options are available:
-c The system is power cycled (power turned off and then back on) at
the specified time. If the hardware doesn't support power cycle,
the system will be rebooted. At the present time, only systems
with BMC supported by the ipmi(4) driver that implement this
functionality support this flag. The amount of time the system
is off is dependent on the device that implements this feature.
-f The shutdown command ignores the presence of the
/var/run/noshutdown file.
-h The system is halted at the specified time.
-p The system is halted and the power is turned off (hardware
support required, otherwise the system is halted) at the
specified time.
-r The system is rebooted at the specified time.
-k Kick everybody off. The -k option does not actually halt the
system, but leaves the system multi-user with logins disabled
(for all but super-user).
-o If one of the -c, -h, -p, or -r options is specified, shutdown
will execute halt(8) or reboot(8) instead of sending a signal to
init(8).
-n If the -o option is specified, prevent the file system cache from
being flushed by passing -n to halt(8) or reboot(8). This option
should probably not be used.
-q Shut down quietly. Suppress the warning message to all logged in
users about system shutdown. It is an error to supply a
warning-message when warnings are suppressed.
time Time is the time at which shutdown will bring the system down and
may be the case-insensitive word now (indicating an immediate
shutdown) or a future time in one of two formats: +number or an
absolute time specification. The first form brings the system
down in number time units (defaulting to minutes), and the second
at the absolute time specified.
An absolute time may be specified in one of the following
formats, where unspecified parts default to the current date:
hhmm Hour and minute.
DDhhmm Day, hour, and minute.
MMDDhhmm Month, day, hour, and minute.
YYMMDDhhmm Year (within the century), month, day, hour, and
minute.
The year YY is interpreted relative to the current century, with
a one-year tolerance for values slightly in the past (to
accommodate entry at year boundaries). +number may be specified
in units other than minutes by appending the corresponding
suffix: "s", "sec", "secs", "m", "min", "mins", "h", "hour",
"hours". The unit suffixes are case-insensitive.
If an absolute time is specified, but not a date, and that time
today has already passed, shutdown will assume that the same time
tomorrow was meant. (If a complete date is specified which has
already passed, shutdown will print an error and exit without
shutting the system down.)
warning-message
Any other arguments comprise the warning message that is
broadcast to users currently logged into the system.
- If `-' is supplied as an option, the warning message is read from
the standard input.
At intervals, becoming more frequent as apocalypse approaches and
starting at ten hours before shutdown, warning messages are displayed on
the terminals of all users logged in. Five minutes before shutdown, or
immediately if shutdown is in less than five minutes, logins are disabled
by creating /var/run/nologin and copying the warning message there. If
this file exists when a user attempts to log in, login(1) prints its
contents and exits. The file is removed just before shutdown exits.
At shutdown time a message is written to the system log, containing the
time of shutdown, the person who initiated the shutdown and the reason.
The corresponding signal is then sent to init(8) to respectively halt,
reboot, or bring the system down to single-user state (depending on the
above options). The time of the shutdown and the warning message are
placed in /var/run/nologin and should be used to inform the users about
when the system will be back up and why it is going down (or anything
else).
A scheduled shutdown can be canceled by killing the shutdown process (a
SIGTERM should suffice). The /var/run/nologin file that shutdown created
will be removed automatically.
If the /var/run/noshutdown file is present, shutdown exits without
executing any action on the system.
When run without options, the shutdown utility will place the system into
single-user mode at the time specified.
Calling "poweroff" is equivalent to running:
shutdown -p now
FILES
/var/run/nologin tells login(1) not to let anyone log in.
/var/run/noshutdown prevents shutdown from initiating an action on the
system. Can be overridden with the -f option.
EXAMPLES
Reboot the system in 30 minutes and display a warning message on the
terminals of all users currently logged in:
# shutdown -r +30 "System will reboot"
Halt the system at 23:30 (using either format):
# shutdown -h 2330
# shutdown -h 23:30
Power off the system on June 15th at 10:00:
# shutdown -p 06151000
COMPATIBILITY
The hours and minutes in any absolute time format may be separated by a
colon (``:'') for backward compatibility. For example, hh:mm is accepted
as equivalent to hhmm.
SEE ALSO
kill(1), login(1), wall(1), nologin(5), halt(8), init(8), reboot(8)
HISTORY
A shutdown command was originally written by Ian Johnstone for UNSW's
modified AT&T UNIX 6th Edn. It was modified and then incorporated in
4.1BSD.
FreeBSD 15.1-STABLE-HBSD December 8, 2025 SHUTDOWN(8)