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SHUTDOWN(8) |
FreeBSD System Manager's Manual |
SHUTDOWN(8) |
shutdown , poweroff —
close down the system at a given time
shutdown |
[- ] [-c |
-h | -p |
-r | -k ]
[-o [-n ]]
time [warning-message
...] |
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.
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.
-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 are
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.
- 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 yymmddhhmm, where
the year, month, and day may be defaulted to the current system values.
The first form brings the system down in number
minutes and the second at the absolute time specified.
+number may be specified in units other than minutes
by appending the corresponding suffix:
“s ”,
“sec ”,
“m ”,
“min ”,
“h ”,
“hour ”.
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 5 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.
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:
- /var/run/nologin
- tells
login(1)
not to let anyone log in
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"
The hours and minutes in the second time format may be separated by a colon
(``:'') for backward compatibility.
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.
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