How to add a US-based keyboard layout with support for german special characters to Ubuntu 18.04

USGermanKeyboardLayoutHowTo.md

Description

How to add a custom keyboard layout based on the standard US layout with slight modifications for german special characters.

• Enter üäöß by pressing right Alt + uaos.
• Enter ÜÄÖẞ by pressing right Alt + Shift + uaos.
• Enter € by pressing right Alt + 5.

HowTo

Add the following lines to end of /usr/share/X11/xkb/symbols/us file

partial alphanumeric_keys
xkb_symbols "us_german" {

  include "us"
  name[Group1]= "US (German)";

  key <AD07> { [ u, U,       U00FC, U00DC] };
  key <AD09> { [ o, O,       U00F6, U00D6] };
  key <AC01> { [ a, A,       U00E4, U00C4] };
  key <AC02> { [ s, S,       U00DF, U1E9E] };
  key <AE05> { [ 5, percent, U20AC       ] };

  include "level3(ralt_switch)"
};

To register the layout you need to modify /usr/share/X11/xkb/rules/evdev.xml. In layoutList search for the layout containing configItem containing <name>us</name> and add the following variant to the variantList

<variant>
  <configItem>
    <name>us_german</name>
    <description>English (US German)</description>
    <languageList>
      <iso639Id>eng</iso639Id>
      <iso639Id>ger</iso639Id>
    </languageList>
  </configItem>
</variant>

To choose this layout in Ubuntu 18.04 restart your PC (log out is not enough). In Settings > Region & Language add another Input Source. Choose English (United States) on the first page and English (US German) on the second.