Stop/resume processes when the user is active/inactive in Linux/Xorg

run_processes_when_idle.sh

#!/bin/bash

# how to identify the processes to STOP/CONT
# this is any part of process command line
PROCESS="myscript.py"

# run this in one terminal:
# it tries to resume the processes every so often
while sleep 10m; do
pgrep -f "${PROCESS}"|xargs -rt kill -CONT
done

# run this in another terminal:
# it stops the processes whenever there is any X event
# all the other stuff is for reducing the number of calls
xinput test-xi2 --root | 
grep --line-buffered EVENT |
while read i; do date +%s; done | stdbuf -oL uniq | 
while read j; do pgrep -f "${PROCESS}" |xargs -rt kill -STOP; done