linux:kernel:sysrq_key
Differences
This shows you the differences between two versions of the page.
| Next revision | Previous revision | ||
| linux:kernel:sysrq_key [2020/03/20 09:45] – created peter | linux:kernel:sysrq_key [2020/07/15 09:30] (current) – external edit 127.0.0.1 | ||
|---|---|---|---|
| Line 50: | Line 50: | ||
| kernel.sysrq = 1 | kernel.sysrq = 1 | ||
| </ | </ | ||
| + | |||
| + | ---- | ||
| + | |||
| + | ===== Useful Key Combinations ===== | ||
| + | |||
| + | Magic SysRq key is to combine of the " | ||
| + | |||
| + | This System Request key is usually sharing its location with the “Print Scrn” key at the top right of your keyboard. | ||
| + | |||
| + | The effect of the combination depends on which letter key is used. | ||
| + | |||
| + | |||
| + | * b – reboots the computer | ||
| + | * e – ask all processes to terminate gracefully | ||
| + | * f – to get rid of an Out Of Memory condition via oom_kills | ||
| + | * i – to kill all processes immediately except init | ||
| + | * k – to kill absolutely all processes, including X | ||
| + | * m – to output the current memory information | ||
| + | * o – to shut down the computer | ||
| + | * r – very useful, to take the keyboard out of the X server control | ||
| + | * s – to sync data from all mounted devices (avoid data loss in case of violent reboot) | ||
| + | * t – to display a list of the current tasks | ||
| + | * u – to remount all file system in read-only mode | ||
| + | |||
| + | ---- | ||
| + | |||
| + | ===== Example - X server is frozen ===== | ||
| + | |||
| + | If your X server is frozen and you cannot access any virtual console, using “Alt + SysRq + r” should take the keyboard away from the X server and let you perform “Ctrl + Alt + F1” in order to get to a terminal and kill the appropriate processes. | ||
| + | |||
| + | If you do not have the patience to do that, “Alt + SysRq + k” will kill everything in the same way as “Ctrl + Alt + Backspace” (but more violently). | ||
| + | |||
| + | If nothing responds at all, and the only way is to reboot your computer, the classical combo is “reisub” for “Raising Elephant Is So Utterly Boring”, or just remember the opposite of “busier“. | ||
| + | |||
| + | * r - Take the keyboard from X | ||
| + | * e - Ask all programs to end gently | ||
| + | * i - Kill the one who did not | ||
| + | * s - Save the data from the cache to the hard drive | ||
| + | * u - Remounts the file systems | ||
| + | * b - Reboot | ||
| + | |||
| ---- | ---- | ||
linux/kernel/sysrq_key.1584697512.txt.gz · Last modified: 2020/07/15 09:30 (external edit)