Remap section sign key (§) to ESC (useful if you have a MacBook Pro with touch bar)

remap_section_to_esc.sh

#!/bin/bash

#
# Remap section sign key (§) to ESC 
#
# 0x700000064 - section sign (§) key below ESC
# 0x700000029 - ESC
#
# https://developer.apple.com/library/content/technotes/tn2450/_index.html
#
# Display current user key mapping setup: 
# $ hidutil property --get "UserKeyMapping"
#
# Reset user key mapping:
# $ hidutil property --set '{"UserKeyMapping": ""}'
#

hidutil property --set '{"UserKeyMapping": [{
  "HIDKeyboardModifierMappingSrc":0x700000064,
  "HIDKeyboardModifierMappingDst":0x700000029
}]}'