HALT(T)        Linux System Administrator's Manual        HALT(T)



NAME
       halt, reboot, poweroff - stop the system.

SYNOPSIS
       /sbin/halt [-n] [-w] [-d] [-f] [-i] [-p] [-h]
       /sbin/reboot [-n] [-w] [-d] [-f] [-i]
       /sbin/poweroff [-n] [-w] [-d] [-f] [-i] [-h]

DESCRIPTION
       Halt  notes  that  the system is being brought down in the
       file /var/log/wtmp, and then either tells  the  kernel  to
       halt, reboot or poweroff the system.

       If halt or reboot is called when the system is not in run-
       level 0 or 6, in other words when it's  running  normally,
       shutdown will be invoked instead (with the -h or -r flag).
       For more info see the shutdown(n) manpage.

       The rest of this manpage describes the behaviour  in  run-
       levels  0 and 6, that is when the systems shutdown scripts
       are being run.

OPTIONS
       -n     Don't sync before reboot or halt.

       -w     Don't actually reboot or halt but  only  write  the
              wtmp record (in the /var/log/wtmp file).

       -d     Don't  write  the  wtmp record. The -n flag implies
              -d.

       -f     Force halt or reboot, don't call shutdown(n).

       -i     Shut down all network interfaces just  before  halt
              or reboot.

       -h     Put  all  harddrives  on the system in standby mode
              just before halt or poweroff.

       -p     When halting the system, do a poweroff. This is the
              default when halt is called as poweroff.

DIAGNOSTICS
       If  you're  not  the  superuser,  you will get the message
       `must be superuser'.

NOTES
       Under older sysvinit releases ,  reboot  and  halt  should
       never  be  called  directly. From release 2.74 on halt and
       reboot invoke shutdown(n) if the system is not in runlevel
       0  or 6. This means that if halt or reboot cannot find out
       the current  runlevel  (for  example,  when  /var/run/utmp
       hasn't   been  initialized  correctly)  shutdown  will  be
       called, which might not be what you want.  Use the -f flag
       if you want to do a hard halt or reboot.

       The -h flag puts all harddisks in standby mode just before
       halt or poweroff. Right now this is only  implemented  for
       IDE  drives. A side effect of putting the drive in standby
       mode is that the write cache on the disk is flushed.  This
       is  important  for  IDE  drives,  since the kernel doesn't
       flush the write-cache itself before poweroff.

       The halt program uses /proc/ide/hd* to find all  IDE  disk
       devices,  which  means that /proc needs to be mounted when
       halt or poweroff is called or the -h switch will do  noth-
       ing.


AUTHOR
       Miquel van Smoorenburg, miquels@cistron.nl

SEE ALSO
       shutdown(n), init(t)



                           Nov 6, 2001                    HALT(T)