A list of magic SysReq keys for the Linux Kernel. Link here.
Press Alt-Sysreq, then one of the following letters:
r | Unraw: Restores the keyboard after an X crash or similar. |
0 | Changes console loglevel to 0 and so reduces error messages. |
k | System attention key: Kills all processes on the current virtual console. |
e | Terminate: Kills all processes except init on the current terminal. |
i | Kill: Kills all processes except init, everywhere. |
s | Sync: Attempts to sync all mounted filesystems. Outputs OK and Done when it's managed. This can reduce the chances of needing to run fsck at a later stage so it can be useful if you're having disk problems. |
u | Umount: Attempts to remount all mounted filesystems read-only. |
b | Reboot: immediately reboots the system without syncing or unmounting disks. Not a good idea unless in extremis! This may lead to data loss. |
p | Dumps current registers and flags to the console. |
m | Dumps current memory info to the console. |