How to enable the Hyper key on Linux

hyper-key.desktop

[Desktop Entry]
Name[en_US]=hyper-key
Comment[en_US]=Set CapsLock to Control and Escape to Hyper
Exec=/usr/local/bin/hyper-key.sh
Icon=application-default-icon
X-GNOME-Autostart-enabled=true
Type=Application

hyper-key.sh

#!/bin/sh
#
# This file contains commands designed to modify an ANSI keyboard
# layout to be more ergonomic and allow a greater range of user-defined
# keybindings by levraging the archaic Hyper key orginally found on
# Symbolics "Space Cadet" keyboards and functionally vestigial in Linux.
# The script can be run standalone to test or set to automatically on
# user login, eg. in $HOME/.config/autostart/hyper-key.desktop

# Start with a clean ANSI US QWERTY layout. This can also be used to
# unset the rest of the configuration commands.
pkill xcape
setxkbmap -layout us

# Abolish CapsLock and replace with Control
setxkbmap -option ctrl:nocaps

# Some Linux distributions like Ubuntu have Hyper set to the same mappings
# as Super (Mod4), so we need to unset those
xmodmap -e "remove Mod4 = Hyper_L"
# Set Escape to be the left Hyper key
xmodmap -e "keycode 9 = Hyper_L"
# Set Hyper_L to use the normally unused Mod3
xmodmap -e "add Mod3 = Hyper_L"

# Set left Control to Escape
xmodmap -e "keycode 37 = Escape"
# Old Escape / new Hyper_L sends Escape when pressed alone
xcape -e '#9=Escape'
# Old CapsLock / new Control_L sends Escape when pressed alone
xcape -e '#66=Escape'

This is an attempt at a more ergonomic programmer's keyboard layout without the need of special hardware (thumb clusters, etc.). With this setup, a user essentially has the entire home row area of the keyboard available for custom hotkeys using something like AutoKey. The default ANSI placement of the left Control key is in my opinion difficult to reach, while hitting the CapsLock or Escape key is easier. By using Hyper instead of Control or Alt for user-defined custom keybindings, there is no risk of accidentally clobbering some existing program's settings. Hyper allows an easy logical separation of concerns for modifier keys: Alt is for application shortcuts, Control is for terminal controls, and Hyper is for user customization.