Alternate Ways To Invoke Magic SysRq
While this was originally implemented as part of the kernel's keyboard handler for debugging, the functionality has been also exposed via the proc filesystem and is commonly used to provide extended management capabilities to headless and remote systems. As an example, shell script can be simply used:
echo b > /proc/sysrq-triggerThis is equivalent to the key combination Alt+SysRq+B which reboots the machine.
The Linux daemons sysrqd and tcpconsole provide a method of accessing SysRq features over a TCP connection after authenticating with a plain-text password.
The Xen hypervisor has functionality to send magic commands to hosted domains via its "xm sysrq" command.
Many embedded systems have no attached keyboard, but instead use a serial console for text input/output to the running system. It is possible to invoke a Magic SysRq feature over a serial console by sending a 'break' serial command, followed by the desired key. The method of sending a break is dependent on the terminal program or hardware used to connect to the serial console.
For minicom, a popular serial terminal program, the command sequence: 'ctrl-a f' will initiate a break sequence. So the command: 'ctrl-a f m' would show memory information about the system.
Read more about this topic: Magic Sys Rq Key
Famous quotes containing the words alternate, ways, invoke and/or magic:
“It might become a wheel spoked red and white
In alternate stripes converging at a point
Of flame on the line, with a second wheel below,
Just rising, accompanying, arranged to cross,
Through weltering illuminations, humps
Of billows, downward, toward the drift-fire shore.”
—Wallace Stevens (1879–1955)
“Malt does more than Milton can
To justify God’s ways to man.”
—A.E. (Alfred Edward)
“Drive a nail home and clinch it so faithfully that you can wake up in the night and think of your work with satisfaction,—a work at which you would not be ashamed to invoke the Muse.”
—Henry David Thoreau (1817–1862)
“Until it is kindled by a spirit as flamingly alive as the one which gave it birth a book is dead to us. Words divested of their magic are but dead hieroglyphs.”
—Henry Miller (1891–1980)