Understanding the SysRq Key - The Magic Key To Control Linux

1. What does the SysRq key do?
2. What does SysRq mean on a keyboard?
3. How do I enable SysRq in Linux?
4. What is Proc SysRq trigger?
5. What key is Scroll Lock?
6. What is the Ctrl Break key?
7. Which key is SysRq?
8. What does F9 do?
9. Where is the pause break key?

What does the SysRq key do?

The magic SysRq key is a key combination understood by the Linux kernel, which allows the user to perform various low-level commands regardless of the system's state. It is often used to recover from freezes, or to reboot a computer without corrupting the filesystem.

What does SysRq mean on a keyboard?

System request (SysRq or Sys Req) is a key on personal computer keyboards that has no standard use. Introduced by IBM with the PC/AT, it was intended to be available as a special key to directly invoke low-level operating system functions with no possibility of conflicting with any existing software.

How do I enable SysRq in Linux?

To enable SysRq temporarily (it falls back to being disabled at the next reboot) you can use the sysctl command: sysctl -w kernel. sysrq=“1” or you can simply echo a 1 to the appropriate procfs leaf: echo “1” > /proc/sys/kernel/sysrq. To persistently enable Magic SysRq keys, you'll need to edit your sysctl. conf file.

What is Proc SysRq trigger?

SysRq or “System Request” is also known as Magic Keys, which allows us to send some specific instructions directly to the Linux kernel. This can be invoked by using a specific keyboard sequence (according to the system hardware) or by echoing letter commands to /proc/sysrq-trigger .

What key is Scroll Lock?

Sometimes abbreviated as ScLk, ScrLk, or Slk, the Scroll Lock key is found on a computer keyboard, often located close to the pause key.

What is the Ctrl Break key?

In a PC, holding down the Ctrl key and pressing the Break key cancels the running program or batch file.

Which key is SysRq?

The SysRq key is located near the Scroll Lock key on your keyboard – the Sys Rq key is generally the same as your Print Screen key. The “magic” SysRq combination is Alt+SysRq.

What does F9 do?

Using the F9 and Fn key at the same time opens Mission Control on an Apple computer running macOS X. In Microsoft Windows, it activates the menu bar of an open application. Shift+F10 is the same as the right-clicking on the highlighted icon, Internet link or file.

Where is the pause break key?

On modern keyboards, the Break key is usually labeled Pause with Break below, sometimes separated by a line: PauseBreak, or Pause on the top of the keycap and Break on the front.