Create xmodmaprc to make VNC usable

altgr_fixed_xmodmaprc.sh

#!/bin/bash
#
# This script executes `xmodmap -pke', modifies the output,
# and prints the result to stdout so that it can be used as
# an xmodmaprc file.
#
# The resulting keymap has AltGr remapped to Mode_switch.
# Existing AltGr-modified key combinations are changed to
# match the new mapping.
#
# This basically just automates a solution outlined by Michael
# Mrozek in this post: https://unix.stackexchange.com/a/302591 
#

xmodmap -pke        \
| sed -r 's, +, ,g' \
| cut -d' ' -f2,4-  \
| while read line; do
  k=($(echo $line))
  if (( "${k[0]}" == 108 )); then
    k=(108 Mode_switch Mode_switch Mode_switch Mode_switch)
  elif (( "${#k[@]}" >= 6 ))      &&
       [[ "${k[1]}" != "${k[5]}"  &&
          "${k[5]}" != 'NoSymbol' ]]; then
    k[3]="${k[5]}"
  fi
  echo keycode ${k[0]} = ${k[1]} ${k[2]} ${k[3]} ${k[4]} ${k[5]} ${k[6]} ${k[7]}
done