Keyboard layout and key mappings

When I switched to i3wm as my main work-horse window manager, I decided to use the “Alt Gr” or “Alt_R” key as the modifier key used for the i3 command shortcuts. The main reason for that comes from my habits to mainly work on workspaces 1 – 5. In order to decrease the stress on my left hand, the modifier should be one key that is controlled by the right hand.

First of all, I had to teach the US layout that the both Alt keys were actually different modifier keys. For this purpose I simply use the xmodmap command:

xmodmap -e 'remove Mod1 = Alt_R'
xmodmap -e 'add Mod3 = Alt_R'

In addition of selecting the “Mod3” key in the i3 config of course. This was working fine as long as I used th US keyboard layout.

Since working at a German university requires some interaction in German from time to time, I had to also have a German keyboard layout available. A short search in the web lead to the suggestion so use the simple setxkbmap command with the desired keyboard layout as follows:

setxkbmap de # For the German keyboard layout
setxbkmap us # For the US keyboard layout

So far so good. I change to the German keyboard layout and received an error message on the console saying that it could not remove the binding of the “Alt_R” symbol as no such mapping exists. I did not pay too much attention to that until I realized that I was unable to control my window manager anymore.

After a little while I finally found out that the “Alt Gr” key is mapped to something called “ISO_Level_3_shift_modifier” in certain keyboard mappings, e.g. the German keyboard mapping. After that I did invest quite some time in trying to figure out how I can resolve that problem and get a fully working German keyboard layout.

I then came across this great article , which explains (for me sufficiently detailed) how the key mapping is done. I was then able to adapt my simple commands to change between keyboard layouts to somewhat more lengthy one:

setxkbmap us; xmodmap -e 'remove Mod1 = Alt_R'; xmodmap -e 'add Mod3 = Alt_R' # For the US layout
setxkbmap de; xmodmap -e 'keycode 108 = Alt_R'; xmodmap -e 'add Mod3 = Alt_R'; xmodmap -e 'keycode 133 = ISO_Level3_Shift' # For the German layout

The additional command for the German keyboard maps the “super” or “Windows” key to the former “Alt Gr” functionality – that is the “ISO_Level_3_shift_modifier”. This is necessary, as on a German keyboard, for example, the ‘@’ sign is placed as a third modifier symbol. Thus, without this functionality available it would be a little less convenient.

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