The "magic sysrq" key sequence is a feature of the Linux kernel that, when enabled, provides debugging and disaster recovery features on the system console and serial console.

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Alt+SysRq+T not working / Where do SysRq commands print to?

My REISUB commands, and K, work flawlesly, but with T (it should print info about tasks), it prints nothing. H also doesn't work. Alt+SysRQ+H Alt+SysRQ+T I tried in all tty's (even F10, which ...
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Why does Alt+SysRq+B not always trigger while REISU do?

On many different machines, when I come across a lockup, I often use Alt+SysRq+REISUB to reboot without too much losses. But I often noticed that although REISU commands work even when I just hold ...
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In Linux, why do you need to be root to write to /proc/sysrq-trigger?

WARNING: THE NEXT KEY COMBINATION WILL CRASH YOUR COMPUTER Ok, I get that this is an administrative tool and all, but I realized that any user can do ALT + SysRq + C. This link explains what I'm ...
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Remote executing Magic Sys Rq

Is it possible to execute Magic SysRq keys on remote machine, using SSH? For example I'm trying to run like this: xdotool key Alt+Sys_Req+H But I do not see any help in console, also in ...
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How long should I wait between keystrokes when doing SysRq + REISUB?

I read this from here: The most useful combination is the Alt+SysRq/Prnt Scrn + R-E-I-S-U-B. The above basically means that while you press and hold Alt+SysRq/Prnt Scrn and press R, E, I, S, ...
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What numeric key codes do I need to send for the magic sysrq functionality in a VNC session?

I have access to the system console of a KVM guest through VNC. What key codes do I need to send for the magic sysrq sequence (Ctrl+Alt+"REISUB") in Linux? Edit: In Linux under qemu, running showkey ...
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how to reboot a frozen FreeBSD server from the serial console?

Linux has the "magic sysrq key" to reboot frozen machines remotely, and it works over the serial console, but what about FreeBSD? Is there a way to send a "control-alt-delete" to FreeBSD servers on ...
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sysrq won't reboot with a keystroke, but will with echo “b” > /proc/sysrq-trigger

CentOS 6.2, 2.6.32-220.el6.x86_64 laptop. SysRQ is enabled for keyboard input, as is witnessed by: $ cat /proc/sys/kernel/sysrq 1 Common Magic SysRQ Keys are working such as alt-sysrq-h. However, ...
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Linux /proc/sys/kernel: where are the files sysrq-sticky, sysrq-key, and sysrq-timer?

Documentation for Red Hat Enterprise Linux 3 (section 5.3.9.3) mentions these files in /proc/sys/kernel/: sysrq sysrq-key sysrq-sticky sysrq-timer The documentation for RHEL 5 also mentions them. ...
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Sysrq keeps taking screen shots

I have enabled SysRq in the kernel like this: $su #echo 1 > /proc/sys/kernel/sysrq and confirmed that it worked. Fn-F1 is my SysRq key, but every time I press Alt-Fn-F1 and any other letter ...
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REISUB (Alt+SysRq+key) doesn't work on Slackware13.37_64, KDE

Under Slackware I never used the magical REISUB, and never used KDE (I don't know if it is important). But now I installed a Slackware13.37_64 with KDE, and, as far as I know, I didn't modify anything ...
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Recovering from Sys Rq + r

I had a really bad lockup of my X server and had to do a Sys Rq + r to release my keyboard from X and get into a console. I was able to kill the process that was locking up my system, and continue my ...
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What does raw/unraw keyboard mode mean?

In the magic sysrq key combinations, there is the combination alt+sysrq+r which, according to wikipedia, does the following: Switch the keyboard from raw mode, the mode used by programs such as ...