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I used to be a Windows user, and when my computer froze I could press CTRL+ALT+Delete and it would restart the computer. Is there a similar function for my current operating system? Thanks everyone.

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3 Answers 3

up vote 4 down vote accepted

Ctrl+Alt+Print Screen+R,E,I,S,U,B (Hold down Ctrl, Alt, and Prnt Scrn then press REISUB in that order with about a second pause between each letter)

This is a functionality that is a part of the Linux kernel (not just Ubuntu). The only catch is that you have to have the keyboard plugged into the computer (doesn't work remotely).

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Press the power button on your keyboard. The system will allow you to select the icon that looks like a power button to turn off the computer. There's a circular arrow that will let you reboot it without powering it down, coming the closest to Windows CTRL-ALT-DELETE.

dash-plus-java's helpful suggestion is good in emergencies when this won't work, but it doesn't allow the various daemon's in your system to terminate normally. (That's not normally a disaster, though).

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@dash-plus-java answered correctly, but not all SysRq keys are enabled by default. Out of the REISUB only U and B are enabled. If you want to enable all SysRqs, do:

echo 1 > /proc/sys/kernel/sysrq

This will enable all sysrqs. If you want just some of them, change the value you echo above, as mentioned in the kernel Docs, https://www.kernel.org/doc/Documentation/sysrq.txt

Now you can press and hold <Alt> <Sys Rq>, and sequentially press R, E, I, S, U and B. Each of them have specific meaning:

  • r - Puts the keyboard into raw mode, taking control of it away from the X server.
  • e - Sends the terminate signal to all processes, asking them to end gracefully.
  • i - Sends the kill signal to all processes, forcing them to end immediately.
  • s - Flushes data from your cache to disk.
  • u - Remounts all file systems read-only.
  • b - Reboots your computer.

More SysRqs:

  • n - Resets the nice level (priority) of all high and realtime priority processes.
  • f - Calls oom_kill, which will kill a memory-hogging process.
  • k - k – Kills all programs on the current virtual console, including X
  • o - Shuts off the computer.
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