HALT(8)		     Linux System Administrator's Manual	      HALT(8)



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 runlevel 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(8)
       manpage.

       The rest of this manpage describes the behaviour in runlevels 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(8).

       -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	supe-
       ruser'.

NOTES
       Under older sysvinit releases , reboot and halt should never be called
       directly. From release 2.74 on halt and reboot invoke  shutdown(8)  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	 ker-
       nel 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 nothing.


AUTHOR
       Miquel van Smoorenburg, miquels@cistron.nl

SEE ALSO
       shutdown(8), init(8)



				 Nov 6, 2001			      HALT(8)

UNIX/Linux commands referenced on this page:

1. halt
2. reboot
3. runlevel
4. shutdown
5. more
6. info
7. sync
8. write
9. as
10. find
11. which