inputplug is a very simple daemon which monitors XInput events and runs
arbitrary scripts on hierarchy change events (such as a device being attached,
removed, enabled or disabled).

For example, inputplug can be used in shell scripts which monitor attachments
of keyboards in order to run change keyboard mappings with commands like
"setxkbmap -option ctrl:nocaps".

WWW: https://github.com/andrewshadura/inputplug