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

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

     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
     entering a shutdown record into the login accounting file and sending a
     message via syslog(3).

     The options are as follows:

     -d      Create a dump before halting or restarting.  This option is
             useful 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
     disabled 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.

NetBSD 6.1.5                   February 16, 2011                  NetBSD 6.1.5