Override keys on macOS in a way that I'm used to

apply-mappings.sh

#!/bin/bash

ERR=`launchctl unload dev.blvckbytes.kbremap.plist 2>&1`
launchctl load dev.blvckbytes.kbremap.plist

[ -z "$ERR" ] && echo "Updated launchd!" || echo "Installed launchd!"

dev.blvckbytes.kbremap.plist

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Label</key>
    <string>kbremap</string>
    
    <!-- Set the target user -->
    <!-- They need to have .config/kbremap/keyremapping.js in ~ (home) -->
    <key>UserName</key>
    <string>blvckbytes</string>

    <key>ProgramArguments</key>
    <array>
        <string>/bin/bash</string>
        <string>-c</string>
        <!-- Get remap file content, strip out comments, join all lines, wrap in single quotes and prefix by the required args, then run that using hidutil -->
        <string>cat ~/.config/kbremap/keyremapping.js | sed -E 's|^([^/]*)//.*$|\1|g' | awk 'BEGIN {ORS=""; print "property --set \x27"} {ORS=""; print} END {ORS=""; print "\x27"}' | xargs hidutil</string>
    </array>

    <key>RunAtLoad</key>
    <true/>
</dict>
</plist>

keyremapping.js

{
  "UserKeyMapping":[
    // CAPS_LOCK to ESCAPE
    {
      "HIDKeyboardModifierMappingSrc": 0x700000039,
      "HIDKeyboardModifierMappingDst": 0x700000029
    },

    // NON_US_BACKSLASH to GRAVE_ACCENT_AND_TILDE
    // On DE this overrides (°/^) with (</>)
    {
      "HIDKeyboardModifierMappingSrc": 0x700000064,
      "HIDKeyboardModifierMappingDst": 0x700000035
    },
    
    // GRAVE_ACCENT_AND_TILDE to NON_US_BACKSLASH
    // On DE this overrides (</>) with (°/^)
    {
      "HIDKeyboardModifierMappingSrc": 0x700000035,
      "HIDKeyboardModifierMappingDst": 0x700000064
    }
  ]
}

reset-mappings.sh

#!/bin/bash

hidutil property --set '{"UserKeyMapping":[]}'
echo "Reset mappings!"