How to set up a custom keyboard layout?

Ubuntu 10.10

I use a local keyboard with US and Thai layout.
The us layout is ok for me, but I like to have some additional german characters like äöü ÄÖÜ This can easy be implemented with xmodmap, but if you switch to the second layout, you will observe some strange results.

I found a good solution: create and use your custom keyboard!

1. /usr/share/X11/xkb/symbols/ choose your nearest preference, in my case us and save it with a new name: us-de

2. delete anything, which you don't need, and change, what ever you like. My file for us-de:

   default
   xkb_symbols "basic" {
   
   name[Group1]= "ASCII with german";
   
   // Alphanumeric section
   key <TLDE> { [ grave, asciitilde ] };
   key <AE01> { [ 1, exclam ] };
   key <AE02> { [ 2, at, twosuperior ] };
   key <AE03> { [ 3, numbersign, threesuperior ] };
   key <AE04> { [ 4, dollar, onequarter ] };
   key <AE05> { [ 5, percent, onehalf ] };
   key <AE06> { [ 6, asciicircum, threequarters ] };
   key <AE07> { [ 7, ampersand ] };
   key <AE08> { [ 8, asterisk, oneeighth ] };
   key <AE09> { [ 9, parenleft ] };
   key <AE10> { [ 0, parenright, degree ] };
   key <AE11> { [ minus, underscore ] };
   key <AE12> { [ equal, plus ] };
   
   key <AD01> { [ q, Q ] };
   key <AD02> { [ w, W ] };
   key <AD03> { [ e, E, EuroSign, cent ] };
   key <AD04> { [ r, R ] };
   key <AD05> { [ t, T ] };
   key <AD06> { [ y, Y ] };
   key <AD07> { [ u, U, udiaeresis, Udiaeresis ] };
   key <AD08> { [ i, I ] };
   key <AD09> { [ o, O, odiaeresis, Odiaeresis ] };
   key <AD10> { [ p, P ] };
   key <AD11> { [ bracketleft, braceleft ] };
   key <AD12> { [ bracketright, braceright ] };
   
   key <AC01> { [ a, A, adiaeresis, Adiaeresis ] };
   key <AC02> { [ s, S ] };
   key <AC03> { [ d, D ] };
   key <AC04> { [ f, F ] };
   key <AC05> { [ g, G ] };
   key <AC06> { [ h, H ] };
   key <AC07> { [ j, J ] };
   key <AC08> { [ k, K ] };
   key <AC09> { [ l, L ] };
   key <AC10> { [ semicolon, colon ] };
   key <AC11> { [ apostrophe, quotedbl ] };
   
   key <AB01> { [ z, Z ] };
   key <AB02> { [ x, X ] };
   key <AB03> { [ c, C ] };
   key <AB04> { [ v, V ] };
   key <AB05> { [ b, B ] };
   key <AB06> { [ n, N ] };
   key <AB07> { [ m, M, mu ] };
   key <AB08> { [ comma, less ] };
   key <AB09> { [ period, greater ] };
   key <AB10> { [ slash, question ] };
   
   key <BKSL> { [ backslash, bar ] };
   key <CAPS> { [ VoidSymbol ] };
   
   // End alphanumeric section
   include "level3(ralt_switch)"
   };
   

3. /usr/share/X11/xkb/rules/evdev.xml Modify evdev.xml so your custom keyboard will be recognised: search for </layoutList> and add the following just before </layoutList>:

   <layout>
   <configItem>
   <name>us-de</name> <!-- a) -->
   <shortDescription>US-DE</shortDescription> <!-- b) -->
   <description>ASCII with german</description> <!-- c) -->
   <languageList><iso639Id>eng</iso639Id></languageList> <!-- d) -->
   </configItem>
   </layout>
   

   • a) us-de is the filename of the new keyboard layout in X11/xkb/symbols
   • b) US-DE this will appear eg. in the indicator applet
   • c) ASCII with german must coincide with the text at the begin of your file:
     name[Group1]= "ASCII with german"; This text will also appear as comment under "Layouts"
   • d) if you choose "eng" your layout will be shown in System->Preferences->Keyboard->tab Layouts->Add->By Language->English under "Variants"

4. log out and log in again, and check System->Preferences->Keyboard->tab Layouts->Add->By Language->English if you can find your custom layout, happy! You are ready to go! Select your first and second layou here. Add a keyboard switcher applet here under "options" you can also disable the CapsLock key.

5. the default keyboard will annoy you and sometime reappear... If you like to get rid of this, edit /var/cache/gdm/$USER/dmrc and place anything existing as your new default: Layout=us-de then reboot.

Based on a post on UbuntuForums.com by Andy Meier at December 28th, 2010.