halt(8) - f7

1HALT(8)               Linux System Administrator's Manual              HALT(8)
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NAME

6       halt, reboot, poweroff - stop the system.
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SYNOPSIS

9       /sbin/halt [-n] [-w] [-d] [-f] [-i] [-p] [-h]
10       /sbin/reboot [-n] [-w] [-d] [-f] [-i]
11       /sbin/poweroff [-n] [-w] [-d] [-f] [-i] [-h]
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DESCRIPTION

14       Halt  notes  that  the  system  is  being  brought  down  in  the  file
15       /var/log/wtmp, and then either tells the  kernel  to  halt,  reboot  or
16       poweroff the system.
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18       If  halt or reboot is called when the system is not in runlevel 0 or 6,
19       in other words when it's running normally,  shutdown  will  be  invoked
20       instead  (with  the  -h  or -r flag). For more info see the shutdown(8)
21       manpage.
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23       The rest of this manpage describes the behaviour in runlevels 0 and  6,
24       that is when the systems shutdown scripts are being run.
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OPTIONS

27       -n     Don't sync before reboot or halt. Note that the kernel and stor‐
28              age drivers may still sync.
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30       -w     Don't actually reboot or halt but only write the wtmp record (in
31              the /var/log/wtmp file).
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33       -d     Don't write the wtmp record. The -n flag implies -d.
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35       -f     Force halt or reboot, don't call shutdown(8).
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37       -i     Shut down all network interfaces just before halt or reboot.
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39       -h     Put  all  harddrives  on  the system in standby mode just before
40              halt or poweroff.
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42       -p     When halting the system, do a poweroff. This is the default when
43              halt is called as poweroff.
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DIAGNOSTICS

46       If  you're  not  the superuser, you will get the message `must be supe‐
47       ruser'.  Users logged in locally on the console can call halt,  reboot,
48       and  poweroff  without  supplying the root password, due to pam_console
49       (8).
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NOTES

52       Under older sysvinit releases , reboot and halt should never be  called
53       directly.  From  release  2.74 on halt and reboot invoke shutdown(8) if
54       the system is not in runlevel 0 or 6. This means that if halt or reboot
55       cannot  find  out the current runlevel (for example, when /var/run/utmp
56       hasn't been initialized correctly) shutdown will be called, which might
57       not be what you want.  Use the -f flag if you want to do a hard halt or
58       reboot.
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60       The -h flag puts all harddisks in standby  mode  just  before  halt  or
61       poweroff.  Right  now  this  is only implemented for IDE drives. A side
62       effect of putting the drive in standby mode is that the write cache  on
63       the disk is flushed. This is important for IDE drives, since the kernel
64       doesn't flush the write-cache itself before poweroff.
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66       The halt program uses /proc/ide/hd* to find all IDE disk devices, which
67       means that /proc needs to be mounted when halt or poweroff is called or
68       the -h switch will do nothing.
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AUTHOR

71       Miquel van Smoorenburg, miquels@cistron.nl
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