I know how to use xmodmap to remap the Caps lock key so it acts as a Control key, or as an Escape key. I would like to combine both features as follows:
When I push, then release, the Caps lock key, it sends Escape. When I hold down Caps lock and push another key (say A), it send Control-A.
Is there some combination of xkb, xmodmap and something else that could make Caps lock behave this way in X?
I'm using Ubuntu Precise on a Macbook Air 3,1.
I have this setup on my Mac and I had tried to find a way for Ubuntu without luck.
Well, it's now working. Thanks tungd for ponting me to xcape. What I have done is really simple and straightforward.
Under System Preferences → Keyboard Layout → Options... → Ctrl key position, I checked Caps Lock as Ctrl.
In a terminal run:
xcape -e 'Control_L=Escape'
Done, Caps Lock works as Ctrl when used like a modifier, and as Esc when pressed alone (there's a slight delay of a few hundred milliseconds, as noted on the xcape README file, so it's still not as optimal as the Mac solution which uses KeyRemap4MacBook.)
I'm looking for this too. As of a week ago I found my self a partial solution using xmodmap:
add Control = Caps_Lock
remove Lock = Caps_Lock
keysym Caps_Lock = Escape
This is of course not working perfectly, it effectively send both Escape and Ctrl at the same time when I press CapsLock, but I was happy with it for a while.
Finally I found this little utility https://github.com/alols/xcape. So now I can simply remap CapsLock to Ctrl and let xcape do its job.
EDIT: Fixed this for most smart (newer) display managers.
Per Louis and Sergiy's comments I have come up with this solution that is working for me on Ubuntu 16.04 (Xenial) with LightDM and Unity.
I put the following line of code into my .xprofile file in my home directory.
setxkbmap -option 'caps:ctrl_modifier' && xcape -e 'Caps_Lock=Escape' &
The trailing & puts the xcape command into the background so that it doesn't block your session. The setxkbmap makes its change immediately.
Sergiy:
I've used gnome-tweak-tool to map Caps Lock to Ctrl as there is no Keyboard layout in System Settings on Ubuntu 14.04. Then xcape -e 'Control_L=Escape' didn't work, but after using xcape -d I've discovered that Caps Lock generates keycode 66 and remapped it respectively: xcape -e '#66=Escape'. – Sergiy Byelozyorov Sep 4 '14 at 10:08
Louis:
As per this blog post, it is possible to do this with xcape alone: setxkbmap -option 'caps:ctrl_modifier' xcape -e 'Caps_Lock=Escape' setxkbmap -option 'caps:ctrl_modifier' xcape -e 'Caps_Lock=Escape;Control_L=Escape;Control_R=Escape' – Louis Simoneau Aug 4 '15 at 10:06
I've built a tool in C specially for this purpose that overcome many of the issues with the xcape/xmodmap solution:
If you are using Gnome, you may find that other answers here result in the key mapping being dropped whenever you connect to bluetooth.
To prevent that from occurring, use the following:
sudo apt install xcape -y; # install the xcape utility, which will be used for caps_lock -> escape
update gnome settings to track the keyboard modifier permanently
gsettings set org.gnome.desktop.input-sources xkb-options "['caps:ctrl_modifier']"; # make caps work as ctrl; https://unix.stackexchange.com/a/66657/77522
make ctrl key work as caps if pressed on its own
xcape -e 'Caps_Lock=Escape' &
sources:
You can do the first (mapping Caps Lock to Esc) but you cannot do the second.
Simple Explanation: Caps Lock is just not designed to do something when pressed.
Elaborate Explanation: There are many types of keys. Two of them are Modifier Keys and Lock Keys.
Caps Lock is a Lock Key while keys such as Ctrl, Alt, and Shift are Modifier Keys.
It's apparent from their names that Modifier Keys modify the function of the next key(s) pressed, and Lock Keys act as a toggle switch to turn on or off some particular function.
Now, since Caps Lock is a Lock Key, you cannot have it behave like a Modifier Key without mapping it to one. Caps Lock by itself cannot function as a Modifier Key.
