halt, reboot, poweroff - stop the system.
notes that the system is being brought down in the file
, and then either tells the kernel to halt, reboot or
power-off the system.
is called when the system is not
, in other words when it's running normally,
will be invoked instead (with the -h
flag). For more info see the shutdown
The rest of this manpage describes the behaviour in runlevels 0 and 6, that is
when the systems shutdown scripts are being run.
- Don't sync before reboot or halt. Note that the kernel and
storage drivers may still sync. This implies -d.
- Don't actually reboot or halt but only write the wtmp
record (in the /var/log/wtmp file).
- Don't write the wtmp record.
- Force halt or reboot, don't call shutdown(8).
- Shut down all network interfaces just before halt or
- Put all hard drives on the system in stand-by mode just
before halt or power-off.
- When halting the system, switch off the power. This is the
default when halt is called as poweroff.
If you're not the superuser, you will get the message `must be superuser'.
Under older sysvinit
releases , reboot
never be called directly. From release 2.74 on halt
(8) if the system is not in runlevel 0 or 6. This means
that if halt
cannot find out the current runlevel (for
example, when /var/run/utmp
hasn't been initialized correctly)
will be called, which might not be what you want. Use the
flag if you want to do a hard halt
flag puts all hard disks in standby mode just before halt or
power-off. Right now this is only implemented for IDE drives. A side effect of
putting the drive in stand-by 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 power-off.
program uses /proc/ide/hd* to find all IDE disk devices, which
means that /proc
needs to be mounted when halt
is called or the -h
switch will do nothing.
Miquel van Smoorenburg, firstname.lastname@example.org