I was researching how to enable the kill X keybind, historically known as CtrlAltBackspace, and stumbled upon this discussion:


There, in post #7, the following was said:

In the versions of X.org-server > 1.6.0 they have disabled 'Zapping'.

In that discusion it was declared that alt-sysreq-k was "better" [than zap] because it's harder to hit accidentally and more reliable due to being implemented in the kernel and not X.

Does that mean that CtrlAltBackspace is officially deprecated? And the replacement is to use AltSysrqK (kill all processes on the current virtual console) instead?

I was not able to find the original source of said discussion. Sadly it was not linked.

Note that the discussion was from 2009.

Note also that I am not asking how to enable CtrlAltBackspace. I am asking whether CtrlAltBackspace is officially deprecated.

  • 2
    How much more "official" would you like than shipping code in the official version of the software? Maybe an embossed certificate to go along with it? Oct 15, 2015 at 18:39
  • I still use it. But then I also have ctrl-alt-del for xkill. ;) Oct 15, 2015 at 19:15
  • 3
    Beware that Ctrl+Alt+Baskspace and Alt+SysRq+K are not equivalent. Ctrl+Alt+Baskspace kills the X server and lets clients live; most clients will die but they can choose to save work. Alt+SysRq+K force-kills everything. Oct 15, 2015 at 22:41

1 Answer 1


The bug tracker entry at https://bugs.freedesktop.org/10510 ("Xorg should use a more unlikely key combination than Control-Alt-Backspace as the server zap key") was closed as "WORKSFORME" after it was pointed out that "zapping [is now] disabled by default", so I guess that's why they saw no more reason to change it. So zapping seems generally deprecated as an everyday feature.

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