Get back the ctrl-alt-backspace behavior in Ubuntu - gHacks Tech News

Get back the ctrl-alt-backspace behavior in Ubuntu

In the most recent release of Ubuntu (9.04) the developers decided (after a very lengthy discussion) that the old tried-and-true Ctrl-Al-Backspace key combination would no longer kill the X server. Their justification for this (in a nutshell) was that this combination could be accidentally hit causing the user to lose data. This was not something they wanted on their hands. To me this is a feature that I would miss. There have been instances where a poorly written application decided it needed to take up all of my memory thereby making the desktop unusable. Of course you could always go to a virtual terminal (as shown in my article "How a virtual console can keep you from losing work") but for new users this is more of a hassle than just being able to hit Ctrl-Alt-Backspace.

Now the problem with Ctrl-Alt-Backspace is that you can, in fact, lose data. But as a last resort, having this behavior back can really be helpful. And fortunately, it is possible to get the old standby behavior back. This tutorial will show you how.

There are two ways to get this behavior back into Ubuntu. You can either install the dontzap application or you can edit your /etc/X11/xorg.conf file. We'll examine both.

Dontzap

The dontzap application does one thing - it sets the DontZap value in xorg.conf so you don't have to. To install the application open up a terminal window and issue the following command:

sudo apt-get install dontzap

Now to set the value in your xorg.conf file you have to run the command with one of two switches:

--enable

or

--disable

To enable the Ctrl-Alt-Backspace behavior you use the --disable switch and to disable the Ctrl-Alt-Backspace behavior use the --enable switch. It seems backwards, but remember the command is dontzap not zap.

So the full command would be either:

sudo dontzap --enable

to disable Ctrl-Alt-Backspace. Or

sudo dontzap --disable

to enable Ctrl-Alt-Backspace.

Once you have run this command you will need to log out of X and log back in, in order for the behavior to finalize.

Manually enabling

If you don't want to install the dontzap application you can hand-edit your xorg.conf file to include the correct DontZap entry. To do this enter the following command to open up your xorg.conf file for editing:

sudo nano /etc/X11/xorg.conf

What you want to do is add the following lines to the end of your file:

Section "ServerFlags"
Option "DontZap" "off"
EndSection

Just as you would have to using the dontzap command, you will have to log out of X and log back in for this to take effect.

Final thoughts

There was a lot of thought and discussion that went into the decision to disable the Ctrl-Alt-Backspace behavior by default. I give the Ubuntu developers a hand for really going out on a limb and thinking more of the new end users than of the old school users like myself. I guess the developers figured it would only be a matter of time before the old school guys would figure out a way to enable this behavior on their systems.

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Comments

  1. yves said on July 31, 2009 at 7:36 pm
    Reply

    Or just use:

    right alt + printscreen +k

    it has the same effect.

    And an other useful trick for the rare occasion that nothing works anymore, try:

    holding down : Alt + printscreen while typing: R E I S U B.

    Safer methode than hitting the PSU Switch. :-)

    cheers
    yves

  2. Mike said on August 1, 2009 at 12:06 am
    Reply

    On suse systems you can hit the ctrl+alt+bs twice to kill X

  3. Janice Acker said on August 1, 2009 at 12:44 am
    Reply

    This is another example of software developers trying to save stupid users from themselves and punishing the rest of us in the process. They go out of their way to remove something that many folks depend on just because “someone might accidentally..”. Well too bad. People who aren’t paying attention to what they’re doing on a computer don’t deserve to use a computer to begin with.

    Dear developers,
    Please put the ctrl+alt+bkspc option back in and stop punishing everyone just because a few stupid people don’t pay attention to what they’re doing on their computers. If you make the stupid ones learn a lesson, they may not be so stupid next time. Or, as a friend puts it, “remove all of the safeties and let the problem take care of itself”.

  4. Yonah said on August 1, 2009 at 1:34 am
    Reply

    Why does Linux allow a poorly written application to impact the system to the point the GUI becomes unusable? Wouldn’t you consider that a serious design flaw?

  5. Jeff said on August 1, 2009 at 2:12 am
    Reply

    Another option is to hit CTRL-ALT-F1 to get to the base command console login prompt, and then CTRL-ALT-F7 to get back to the graphical X desktop — usually works even when resources are tied up, and then you can get an unencumbered console going to fix whatever needs help.

  6. Reign of Seven said on August 1, 2009 at 3:31 am
    Reply

    Linux doesnt control all the applications that are installed on your system. there are 6 billion people on the planet right now and all 6 billion can write their own programs and install them. It has nothing to do with Linux, its WHERE the person installs the application from.

    Which is why we emphatically urge people to ONLY install STABLE packages from your Distro’s package manager.

  7. Anonymous said on August 1, 2009 at 4:02 am
    Reply

    @Yonah:

    The GUI system is not part of the Linux kernel, but runs as just another operating system process. Rephrase your question a little bit, and the answer becomes self-evident: “Why would Linux allow a poorly written application to not accept user input?”

    The answer: Linux is not responsible for an application’s processing of user input. The application (in this case, X) is responsible for processing its user input.

  8. Anonymous said on August 1, 2009 at 4:04 am
    Reply

    This is an X.org thing, not just an Ubuntu thing.

  9. Anonymous said on August 1, 2009 at 4:20 am
    Reply

    There is a rule in software evolution : when a useful
    functionality that has been around for years becomes an option, the default new value of the option must be the same as the old way.

    X.org developers are dumb.

  10. oiaohm said on August 1, 2009 at 8:12 am
    Reply

    Everyone is being dumb.

    alt-ctrl-backspace was removed because it don’t work correctly. X11 locks up and it don’t work.

    http://www.mjmwired.net/kernel/Documentation/SAK.txt << It would be better to assign ctrl-alt-backspace to this. Result is basically the same but is way more dependable only fails to work if the kernel is paniced. Not like old X11 zap that X11 server locked up causes it not to happen..

    right alt + printscreen +k is no longer recommended. It is not way near as clean as the other SAK combination.

    Basically stop putting back a feature that does not work correct its broken move on. Use the feature that works correctly in kernel based SAK.

    Distributions have been lazy.

  11. David said on August 3, 2009 at 10:44 am
    Reply

    Ubuntu getc less comfortable every release. For all kinds of stuff that worked flawless you have to find workarounds. The developers were just thinking nothing. They are just annoying the users.

    Anyway, thanks for your article, now I can zap my x-server again.

  12. Anonymous said on August 3, 2009 at 1:08 pm
    Reply

    Not being able to use Ctrl-Alt-Backspace I am afraid lots of people having a non responding machine, will solve this by rebooting the pc the hard way, simply by hitting the power button. This uncontrolled shutdown will lead to errors in the file-system. These are generally automatically resolved, but on some rare occasions you end up having to run fsck manually on boot. This is however impossible unless you have enabled the root account. The password required in these circumstances is the root password and not the “Sudo” password. To clean up your system you need to boot from a recovery CD/DVD or similar media, but how many have these readily available and know how to do this?

  13. jklowden said on August 3, 2009 at 4:19 pm
    Reply

    “dontzap” is an unfortunate choice for a name. It’s a utility to disable something, which is confusing. What does “dont zap –enable” mean, in English?

    Imagine chmod(2) were named “prevent” because it’s used to prevent access to files. Then “prevent g-w” would mean … huh?

    Better would have been “ctrl-alt-backspace”:

    ctrl-alt-backspace –enable and
    ctrl-alt-backspace –disable

    are both clear and unambiguous.

  14. James D said on August 3, 2009 at 4:44 pm
    Reply

    I’m sorry, but the real story is that this was forced into Ubuntu by a specific clique of old school users, namely those who use a common piece of virtualization software. The genius who designed that mapped a common shortcut onto Ctrl+Alt+Enter, not realizing that the Enter and Backspace keys are adjacent on the British keyboard layout. The correct solution would have been to fix the virtualization software’s shortcuts to be less US-centric, but instead they decide to screw over every new end user of X by breaking the documentation-by-search-engine approach.

  15. Mike said on August 20, 2009 at 8:58 pm
    Reply

    ctrl-alt-bkspc is a partially graceful way of restoring Ubuntu which regularly hangs and freezes, exclusively running the software suite on the Hardy Heron LiveCD which is notoriously unstable

    The software complement currently invoked is pooched anyway when the 8.04 system freezes but at least there’s half a chance the desktop maybe recovered short of a complete hard reboot.

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