SHUTDOWN(8) BSD System Manager's Manual SHUTDOWN(8)
shutdown - close down the system at a given time
shutdown [-] [-fhkrn] time [warning-message ...]
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.
-f Shutdown arranges, in the manner of fastboot(8), for the file sys-
tems not to be checked on reboot.
-h The system is halted at the specified time when shutdown execs
-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
-n Prevent the normal sync(2) before stopping.
-r Shutdown execs reboot(8) at the specified time.
time Time is the time at which shutdown will bring the system down and
may be the word now (indicating an immediate shutdown) or specify 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.
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 start-
ing at ten hours before shutdown, warning messages are displayed on the
terminals of all users logged in. Five minutes before shutdown, or imme-
diately if shutdown is in less than 5 minutes, 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(1) prints its contents
and exits. The file is removed just before 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. A terminate
signal is then sent to init to bring the system down to single-user state
(depending on above options). The time of the shutdown and the warning
message are placed in /etc/nologin and should be used to inform the users
about when the system will be back up and why it is going down (or any-
/etc/nologin tells login not to let anyone log in
/fastboot tells rc(8) not to run fsck when rebooting
login(1), wall(1), fastboot(8), halt(8), reboot(8)
The hours and minutes in the second time format may be separated by a
colon (``:'') for backward compatibility.
The shutdown command appeared in 4.0BSD.
4th Berkeley Distribution April 27, 1995 2