# Linux SysRq howto
# CraigT <some.person@bbc.co.uk>
# v0.1 20060523

SysRq allows you to send controls to the linux kernel. This can help you
recover a machine that you are having difficulty restarting etc.

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It can be initiated in two ways:
Video console:
<Alt>+<SysRq> + <desired command>

Serial console:
<send brk> + <desired command>

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Key definitions:
r - the keyboard mode is reset to K_XLATE.
k - a SAK and console reset is done.
b - the machine is rebooted immediately.
o - the power is turned off (when the machine is capable of that).
s - an emergency sync is scheduled.
u - an emergency read-only emount is scheduled.
p,t,m - various information is shown (namely the same information
        also shown for RAlt,RCtrl,RShift+ScrollLock).
e,i,l - all processes get a SIG_TERM or SIG_KILL, respectively;
        for l even the init process is killed.
0-8 - Digits set the log level.

Anything else prints a short summary:
SysRq: unRaw saK Boot Off Sync Unmount showPc showTasks showMem loglevel0-8 tErm kIll killalL

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it can be enabled in two ways:

	echo 1 > /proc/sys/kernel/sysrq

or by editing /etc/sysctl.conf to include:

	kernel.sysrq = 1

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