Ubuntu – Left Alt key should work as right Alt key (Alt Gr)

You should be able to simply use Keyboard Layout >> Options >> Ctrl key position >> Right Alt as Right Ctrl, but this doesn't work. This has already been filed against Debian as Bug#663218

1. Start fresh by deleting ~/.Xmodmap.

2. Note that you do not need to clear Control and Mod1. This makes it easier to change only what you want. Your ~/.Xmodmap shoud be:

   !Swap right control and right alt
   remove Control = Control_R
   remove Mod1 = Alt_R
   keycode 105 = Alt_R
   keycode 108 = Control_R
   add Control = Control_R
   add Mod1 = Alt_R
   

Ok, yet another try, this one will do the trick I hope... ;)

Credits are due to reverendj1, who described a way of assigning a Custom key to toggle keyboard layout, using setxkbmap, which featured in the workaround alluded to in Edit 2 of my previous answer...

Here is the slightly more involved way, but will give you more flexibility for the key combination. First, copy and paste this script I wrote and name it something like kb_toggle.sh. Make sure to edit LANG1 and LANG2 to be the keyboard layout codes you need.

#!/bin/bash

LANG1="us"
LANG2="de"
CURRENT_LANG=$(setxkbmap -query | tail -n 1 | cut -f6 -d ' ')
if [ "$CURRENT_LANG" = $LANG1 ]; then
    setxkbmap $LANG2
else
    setxkbmap $LANG1
fi

make the file by right-clicking on it -> "Properties" -> "Permissions" tab, then select "Allow executing file as program.

Now, open "System Settings" -> "Keyboard" -> "Shortcuts" tab and select "Custom Shortcuts". Click the + button on the bottom and name the shortcut "Keyboard Toggle" or whatever you want, really. Then give the full path to the script you made earlier in the command box. Hit Apply. Click where it says "Disabled" then you can set the shortcut to whatever you want by clicking your key combination!

I think you'd need to change "de" to "ir".

Again, good luck!

Edit

You may even get away with a one-liner, if you prefer:

setxkbmap us,ir -option "grp:alt_shift_toggle"

Now you can switch by pressing alt+shift

See also http://wiki.lxde.org/en/Change_keyboard_layouts and http://www.x.org/releases/X11R7.7/doc/man/man1/setxkbmap.1.xhtml

Edit 2

Depending on how you decide to achieve your goal, you may want to include lv3:ralt_alt in your command, resulting in

setxkbmap us,ir -option "lv3:ralt_alt,grp:alt_shift_toggle"

See man xkeyboard-config | grep lv3 for details:

lv3:ralt_alt

Right Alt key never chooses 3rd level

   xkeyboard-config  provides  the  description files for the X Keyboard Extension (XKB). The configuration options below are
   usually applied with setxkbmap(1).