About GUI widgets.
-*- mode: outline; coding: utf-8 -*-
* SysRq.
x86: ALT-SysRq-<command key>
SPARC: ALT-STOP-<command key>
PPC: ALT - Print Screen (or F13) - <command key>
'b' - reboot
'p' - dump the current registers and flags to your console
'r' - take control of keyboard back from X
'e' - send SIGTERM to all processes, except for init
'i' - send SIGKILL to all processes, except for init
's' - attempt to sync all mounted filesystems
'u' - remount all filesystems read-only
You can put one of such line:
$ echo 0 > /proc/sys/kernel/sysrq # disable
$ echo 1 > /proc/sys/kernel/sysrq # enable
to your /etc/rc.local or alternativaly place under /etc/sysctl:
kernel.sysrq = 1
http://www.kernel.org/doc/Documentation/sysrq.txt
Linux Magic System Request Key Hacks