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REBOOT(8)		  BSD System Manager's Manual		     REBOOT(8)

     reboot, poweroff, halt -- restarting, powering down and stopping the sys-

     halt [-dlnpqvxz]
     poweroff [-dlnqvxz]
     reboot [-dlnqvxz] [arg ...]

     The poweroff, halt	and reboot utilities flush the file system cache to
     disk, send	all running processes a	SIGTERM, wait for up to	30 seconds for
     them to die, send a SIGKILL to the	survivors and, respectively, power
     down, halt	or restart the system.	The action is logged, including	enter-
     ing a shutdown record into	the login accounting file and sending a	mes-
     sage via syslog(3).

     The options are as	follows:

     -d	     Create a dump before halting or restarting.  This option is use-
	     ful for debugging system dump procedures or capturing the state
	     of	a corrupted or misbehaving system.

     -l	     Suppress sending a	message	via syslog(3) before halting or

     -n	     Do	not flush the file system cache.  This option should be	used
	     with extreme caution.  It can be used if a	disk or	a processor is
	     on	fire.

     -p	     Attempt to	powerdown the system.  If the powerdown	fails, or the
	     system does not support software powerdown, the system will halt.
	     This option is only valid for halt.

     -v	     To	enable verbose messages	on the console,	pass the boothowto(9)
	     flag AB_VERBOSE to	reboot(2).

     -x	     To	enable debugging messages on the console, pass the
	     boothowto(9) flag AB_DEBUG	to reboot(2).

     -z	     To	silence	some shutdown messages on the console, pass the
	     boothowto(9) flag AB_SILENT to reboot(2).

     -q	     Do	not give processes a chance to shut down before	halting	or
	     restarting.  This option should not normally be used.

     If	there are any arguments	passed to reboot they are concatenated with
     spaces and	passed as bootstr to the reboot(2) system call.	 The string is
     passed to the firmware on platforms that support it.

     Normally, the shutdown(8) utility is used when the	system needs to	be
     halted or restarted, giving users advance warning of their	impending

     reboot(2),	syslog(3), utmp(5), boot(8), init(8), rescue(8), shutdown(8),

     A reboot command appeared in Version 6 AT&T UNIX.

     The poweroff command first	appeared in NetBSD 1.5.

     Once the command has begun	its work, stopping it before it	completes will
     probably result in	a system so crippled it	must be	physically reset.  To
     prevent premature termination, the	command	blocks many signals early in
     its execution.  However, nothing can defend against deliberate attempts
     to	evade this.

     This command will stop the	system without running any shutdown(8)
     scripts.  Amongst other things, this means	that swapping will not be dis-
     abled so that raid(4) can shutdown	cleanly.  You should normally use
     shutdown(8) unless	you are	running	in single user mode.

     The single	user shell will	ignore the SIGTERM signal.  To avoid waiting
     for the timeout when rebooting or halting from the	single user shell, you
     have to exec reboot or exec halt.

BSD			       February	16, 2011			   BSD


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