SHUTDOWN(8) | System Manager's Manual | SHUTDOWN(8) |
shutdown
— close
down the system at a given time
shutdown |
[- ] [-dfhknpr ]
time [warning-message
...] |
shutdown
provides an automated shutdown
procedure for superusers 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. When the
shutdown
command is issued without options the
system is placed in single user mode at the indicated time after shutting
down all system services.
The options are as follows:
-d
-h
, -p
, or
-r
causes system to perform a dump. This option is
useful for debugging system dump procedures or capturing the state of a
corrupted or misbehaving system. See
savecore(8) for
information on how to recover this dump.-f
-h
shutdown
execs
halt(8).-k
-k
option does not
actually halt the system, but leaves the system multi-user with logins
disabled (for all but superuser).-n
-h
, -p
, or
-r
prevents the normal
sync(2) before stopping the
system.-p
-p
flag is passed on to
halt(8), causing machines
which support automatic power down to do so after halting.-r
shutdown
execs
reboot(8) at the specified
time.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.-
-
’ 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 /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 anything else).
You can cancel a scheduled shutdown with the kill(1) command by killing the shutdown process.
kill(1), login(1), wall(1), halt(8), rc.shutdown(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.
January 21, 2015 | OpenBSD-6.4 |