/sbin/shutdown [-t sec] [-arkhncfFHP]
messageand logins are disabled.
SIGTERM. This gives programs like editors the time to save the file being edited, mail and news processing programs a chance to exit cleanly, etc.
SIGKILLto all processes
/etc/inittabdefines what action is taken for halt or reboot.
/etc/nologin is created if
shutdown is called with a delay.
This causes programs such as
login to deny logins.
Shutdown removes this file if it is stopped before it signals
init (i.e. it is cancelled or something goes wrong).
/etc/nologin before calling
init to change the runlevel.
CTRL-ALT-DELare pressed, by creating an appropriate entry in
/etc/inittab. This means that everyone who has physical access to the console keyboard can shut the system down. To prevent this, shutdown can check to see if an authorized user is logged in on one of the virtual consoles. If shutdown is called with
-a(add this to the invocation of shutdown in
/etc/inittab), it checks to see if the file
/etc/shutdown.allowis present. It then compares the login names in that file with the list of people that are logged in on a virtual console (from
/var/run/utmp). Only if one of those authorized users or root is logged in, it will proceed. Otherwise it will write the message
to the (physical) system console.
shutdown: no authorized users logged in
/etc/shutdown.allowis one user name per line. Empty lines and comment lines (prefixed by a #) are allowed. There is a limit of 32 users in this file. Note that if
/etc/shutdown.allowis not present, the
-Hoption just sets the init environment variable
HALT, and the
-Pjust sets that variable to
POWEROFF. The shutdown script that calls halt as the last thing in the shutdown sequence should check these environment variables and call halt with the right options for these options to actually have any effect. Debian 3.1 (sarge) supports this.
time argument is mandatory
[CTRL]-[ALT]-[DEL] will start
shutdown from a console
in text mode.
If the console is running a window System, the windows server processes key strokes and processing of
[CTRL]-[ALT]-[DEL] is server dependent.
Shutdown wasn't designed to be run setuid.
/etc/shutdown.allow is not used to find out who
is executing shutdown, it ONLY checks who is currently logged in on (one of the) console(s).
-n If -o is specified, prevent the file system cache from being flushed by passing -n option to halt or reboot. This option should not be used.
*** System shutdown message from email@example.comName ***
Starting at no more than 10 hours before shutdown, at intervals becoming more frequent
5 minutes before shutdown, or immediately if shutdown is in less than 5 minutes,
A scheduled shutdown can be canceled by reporting
SEE ALSO kill(1), login(1), wall(1), nologin(5), halt(8), init(8), reboot(8)
shutdown [/i ]
Reasons on this computer: (E = Expected U = Unexpected P = planned, C = customer defined) Type Major Minor Title EU 0 0 Other (Unplanned) E P 0 0 Other (Planned) U 0 5 Other Failure: System Unresponsive E P 1 1 Hardware: Maintenance (Unplanned) E P 1 2 Hardware: Installation (Planned) E P 2 2 Operating System: Recovery (Planned) P 2 3 Operating System: Upgrade (Planned) E P 2 4 Operating System: Reconfiguration (Planned) P 2 16 Operating System: Service pack (Planned) P 2 17 Operating System: Hot fix (Planned) P 2 18 Operating System: Security fix (Planned) E P 4 1 Application: Maintenance (Planned) E P 4 2 Application: Installation (Planned) E 4 5 Application: Unresponsive E 4 6 Application: Unstable U 5 15 System Failure: Stop error EUP 5 19 Security issue E 5 20 Loss of network connectivity (Unplanned) U 6 11 Power Failure: Cord Unplugged U 6 12 Power Failure: Environment P 7 0 Legacy API shutdown