Dale's Random Ramblings ;-)

FOSSwire has an interesting article explaining how to get back on your Linux box when it appears to be frozen without having to resort to the power button.

• Hold down the Alt and SysRq (Print Screen) keys.
• While holding those down, type the following in order. Nothing will appear to happen until the last letter is pressed: REISUB
• Watch your computer reboot magically.

“Raising Elephants Is So Utterly Bonkers” is a way of remembering the keystroke sequence.

The key combination consists of Alt, SysRq and another key, which controls the command issued:

• 0 through 9 sets the console log level, which controls the types of kernel messages that are output to the console.
• b immediately reboots the system, without unmounting partitions or syncing.
• c reboots kexec and outputs a crashdump.
• e sends the SIGTERM signal to all processes except init (PID 1).
• f calls oom_kill, which will kill a process that is consuming all available memory.
• h, or any key which is not bound to a command, outputs a terse help document to the console.
• i sends the SIGKILL signal to all processes except init.
• k kills all processes on the current virtual console (and thus can be used to kill X and svgalib programs, see below). This was originally designed to imitate a Secure Access Key.
• l sends the SIGKILL signal to all processes, including init.
• m outputs current memory information to the console.
• o shuts off the system.
• p outputs the current registers and flags to the console.
• r switches the keyboard from raw mode, the mode used by programs such as X11 and svgalib, to XLATE mode.
• s attempts to sync all mounted filesystems.
• t outputs a list of current tasks and their information to the console.
• u attempts to remount all mounted filesystems in read-only mode.
• v outputs Voyager SMP processor information.

References