SHUTDOWN(8) System Administration SHUTDOWN(8)
shutdown - close down the system at a given time
shutdown [ - ] [ -hkrn ] 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.
h The system is halted at the specified time when shutdown
k Kick every body off. The k option does not actually halt
the system, but leaves the system multi-user with logins
disabled (for all but super-user).
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
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 dis-
abled 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 termi-
nate 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 anything else).
tells login not to let anyone log in
login(1), wall(1), 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.
GNO 4 October 1997 SHUTDOWN(8)
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