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Using Caps Lock as an extra Control key

With me mostly posting about computer stuff on this weblog, it might surprise you that, until May this year, I hadn’t owned a personal computer in years while the last one that I did own was a slow pig grown from some old parts of an even slower pig and some second-hand replacements. So, you can image my joy when I got a shiny, new Lenovo Thinkpad 61 this spring.

One of the joys of once more owning a personal computer is that I don’t have to live through PuTTY anymore. (I used to SSH to the local Debian server here if I wanted to get anything done.) I’ve reacquainted myself with Gentoo and I’m loving it. Of course, there’s a lot more to configure than with Ubuntu (which supports the T61 very neatly out of the box), but that’s the whole point; I want to be able to configure everything my way and I want to update my knowledge about how Linux systems are made up these days. Control.

On the topic of control, the Control key on the Lenovo keyboard, as with many laptop keyboards that I’ve encountered, is in a bit of an awkward position, squeezed to the right by the Function key. Since, I very much depend on the Control key for shortcuts (in just about anything, but especially in libreadline-based programs), I decided to change the Caps Lock key to be an extra Control key. I’ve never actually used the CapsLock key in my life, I probably never will, older keyboards used that very spot for the Control Key, and why not? It’s a much better spot, requiring less gymnastics for my little pinky to reach. Once I considered this I was actually puzzled about why I’ve always wasted such an well-accessible key position.


On to the configuration. I wanted this to work in both Console mode and in X. But first X. In the xorg.conf, I went to the InputDevice section for my keyboard and added ctrl:nocaps to XkbOptions. The full XkbOptions line now reads:

Option "XkbOptions" "ctrl:nocaps,altwin:menu,compose:ralt,eurosign:e"

That’s it. I had to take a few more steps to get it to work in the console also.


First, I created a file called “/etc/extra-key-conf” with the following contents:

keymaps 0-15
keycode 58 = Control

Then I added the following to /etc/conf.d/local.start. This is a Gentoo specific script that is loaded by /etc/init.d/local.

[ -z "$DISPLAY" -a -e /etc/extra-key-conf ];
        loadkeys /etc/extra-key-conf &>/dev/null

What this does is to check if the $DISPLAY variable isn’t set (of which we can be sure in this context, but may be useful if you plan to copy this snippet). It also checks if /etc/extra-key-conf exists. If both conditions are satisfied, loadkeys is called with that file as its argument.

In conclusion

I can really recommend this configuration even if your Control key is not awkwardly positioned on your keyboard. Do you use your Caps Lock key? Regularly? If you don’t, this will make your keyboard use more effective.


If you want to read into this more extensively, I recommend the Remap Caps Lock article from the Portland Pattern Repository.


  1. halfgaar

    I also made my capslock a control key a while ago, but for some reason, this doesn’t work in Warcraft I (and probably in all of Dosbox). That’s quite a bummer, because I need control a lot in Warcraft.

    Apparently, Dosbox or Warcraft doesn’t use the X key mappings.

    It does work in Wine; control is one of my Half-Life 2 keys.

  2. Rowan Rodrik

    For some reason, this no longer worked today when I booted my laptop, while my last full upgrade was some time ago. The only thing system-related I did yesterday was running a full system backup with rsync. I’m dumbfounded.

    I added the following to my .xinitrc to make it work again:

    setxkbmap -layout us -option ctrl:nocaps

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