SHUTDOWN(8) BSD System Manager's Manual SHUTDOWN(8)NAMEshutdown - close down the system at a given time
SYNOPSISshutdown [-] [-chkrn] +minutes | [[[yy]mm]dd]hhmm [message ...]
DESCRIPTION
Shutdown 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 Cancel any previously started shutdown.
-h Cause shutdown to halt the system at the specified time, using
halt(8).
-k Kick everybody off. The -k option does not actually halt the sys-
tem, but leaves the system multi-user with logins disabled (for all
but super-user).
-n Prevent the normal sync(2) before stopping.
-r Cause shutdown to reboot the system at the specified time, using
reboot(8).
time Time is the time at which shutdown will bring the system down and
may be the word ``now'' (indicating an immediate shutdown) or may
specify a future time. A future time may be specified in one of
two formats: +number, which specifies number minutes, and
[[[yy]mm]dd]hhmm, which specifies an absolute time where the year,
month and day default to the current system time.
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.
Periodically, starting ten hours before the specified time, and becoming
more frequent as apocalypse approaches, warning messages are displayed
for all logged in users. Five minutes before shutdown, or immediately if
shutdown is in less than 5 minutes away, logins are disabled by creating
/etc/nologin and copying the warning message there. If this file exists
when a user attempts to log in, login(8) displays its contents and refus-
es the attempt. If shutdown does not execute halt(8) or reboot(8), and
the -k option was not specified, this file will be removed when shutdown
exits.
At shutdown time a message is written in the system log, containing the
time of shutdown, who initiated the shutdown and the reason. Then, if
none of the -h, -k or -r, options were specified, a terminate (SIGTERM)
signal is sent to the init(8) process to return the system to single-user
state.
FILES
/etc/nologin tells login not to let anyone log in
/var/run/shutdown.pid the process ID of the currently running shutdownSEE ALSOwall(1), halt(8), login(8), reboot(8)BACKWARD COMPATIBILITY
The hours and minutes in the absolute time format may be separated by a
colon (``:'') for backward compatibility.
Historically, the -f option to shutdown arranged for the file systems not
to be checked on reboot. As filesystems are no longer checked unless
necessary, this option has no effect.
HISTORY
The shutdown command appeared in 4.0BSD.
4th Berkeley Distribution April 27, 1995 2