|Mac OS version Windows|
nowor at another
/sbin/shutdown [-t sec] [-arkhncfFHP]
syslogmessage is NOT sent! (see
/usr/local/bin | ~/bin)
messageand logins are disabled.
SIGTERM. This gives programs like editors the time to save the file being edited, other programs a chance to exit cleanly
SIGKILLto all processes
-ris given to shutdown
/etc/inittabdefines the action is taken for halt or reboot.
time can be of the form:
message sent to all users.
/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.
initwhen the magic keys
CTRL-ALT-DELare pressed, by creating an appropriate entry in
-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.allowhas 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.
/etc/shutdown.allow is not present, the
-a is ignored.
-Hsets the init environment variable
HALT, and the
-Psets that variable to
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.
/etc/shutdown.allow does not chwck who invoked shutdown, ONLY who is 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 firstname.lastname@example.orgName ***
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)
Reasons: Expected Unexpected Planned, Type Major Minor Title EU 0 0 Other E P U 0 5 Other Failure: System Unresponsive E P 1 1 Hardware: Maintenance (Unplanned) E P 1 2 Hardware: Installation E P 2 2 Operating System: Recovery P 2 3 Operating System: Upgrade E P 2 4 Operating System: Reconfiguration P 2 16 Operating System: Service pack P 2 17 Operating System: Hot fix P 2 18 Operating System: Security fix E P 4 1 Application: Maintenance E P 4 2 Application: Installation 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: power loss U 6 12 Power Failure: Environment P 7 0 Legacy API shutdown
/sbin/halt [-n] [-w] [-d] [-f] [-i] [-p] [-h]
/sbin/reboot [-n] [-w] [-d] [-f] [-i]
/sbin/poweroff [-n] [-w] [-d] [-f] [-i] [-h]
halt notes that the system is being brought down in the file
then tells the kernel to halt, reboot or power-off the system.
-d Don't write the wtmp record. (see
last-w write the wtmp record (in
/var/log/wtmp). Don't reboot or halt -n Don't sync before reboot or halt. Note that the kernel and storage drivers may still sync. implies -d. -f Force halt or reboot, don't call shutdown(8). -i interfaces for networks are shutdown just before halt or reboot. -h hard drives put in stand-by mode just before halt or power-off, causing the write cache on the disk to be flushed. -p poweroff When halting the system
shutdown(8)if the system is not in runlevel 0 or 6.
shutdown - bring the system down
/sbin/shutdown [-akrhPHfFnc] [-t sec] time [warning message]
shutdown brings the system down in a secure way. users are notified
that the system is going down, and login(1) is blocked.u
It is possible to shut the system down immediately or after a specified delay.
All processes are first notified that the system is going down by the signal SIGTERM. This gives programs like vi(1) the time to save the file being edited, mail and news processing programs a chance to exit cleanly, etc.
shutdown signals the init process, to change the runlevel. Runlevel 0 is used to halt the system, runlevel 6 is used to reboot the system, and runlevel 1 is used to put to system into a state where administrative tasks can be performed; this is the default if neither the -h or -r flag is given to shutdown. Actions are taken on halt or reboot are in the file
time can have format:
+mthe number of minutes to wait.
/etc/nologinwhich causes programs such as login(1) to not allow new user logins.
130time could not be parsed