SHUTDOWN(8) | System Manager's Manual | SHUTDOWN(8) |
shutdown
— close
down the system at a given time
shutdown |
[-Ddfhknprvxz ] [-b
bootstr] time
[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.
Available friendlinesses:
-b
bootstr-d
shutdown
will pass the -d
flag to reboot(8) or
halt(8) to request a kernel
core dump. If neither the -h
nor
-r
flags are specified, then
-d
also implies -r
.-f
shutdown
arranges, in the manner of
fastboot(8), for the file
systems not to be checked on reboot.-h
-k
-k
option does not
actually halt the system, but leaves the system multi-user with logins
disabled (for all but super-user).-n
-p
-r
-v
-v
to reboot(8) or
halt(8).-x
-x
to
reboot(8) or
halt(8).-z
-z
to
reboot(8) or
halt(8).-D
shutdown
from detaching from the tty with
fork(2)
/
exit(3).shutdown
will bring the system
down and may be the word now
or a future time in
one of two formats: +
number,
or
[[[[[cc]yy]mm]dd]hh]mm,
where the century, year, month, day, and hour are two digit decimal
values, which may be defaulted to the current system values. The two digit
(decimal, even with a leading zero) minute field is required in this form.
The first form brings the system down number minutes
from the current time; the second brings the system down at the absolute
time specified. If the century is not specified, but the year is, the
century defaults to 2000 (cc =
20, the 21st century) for years between 20 and 99, or 2100 for
years between 0 and 19. A leading zero in the yy
value (as with all the others) is not optional.-
-
is supplied as the only argument after the
time, 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.
Next a message is printed announcing the start of the system shutdown hooks.
Then the shutdown hooks in /etc/rc.shutdown are run,
and a message is printed indicating that they have completed. After a short
delay, shutdown
runs
halt(8) or
reboot(8), or sends a
terminate signal to init(8) to
bring the system down to single-user mode, depending on the choice of
options.
The time of the shutdown and the warning message are placed in /etc/nologin and should be used to tell the users why the system is going down, when it will be back up, and to share any other pertinent information.
login(1), wall(1), fastboot(8), halt(8), init(8), poweroff(8), reboot(8), rescue(8)
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 Version 6
AT&T UNIX, modified, and then incorporated in
4.1BSD.
February 14, 2023 | NetBSD 10.99 |