As Jan Hovancik has done a great job developing Stretchly, I switched to this software and no longer use the bare script.
So you sit in front of your computer running linux OS for like several hours? Try this
Python script whenever you start using your computer. It forces you to stand up and have
a quick 2 minutes rest by lowering your screen brightness level down to zero. Don't worry
though, you may increase your screen brightness level immediately.
Run the following command in your terminal and every 20 minutes your screen goes off for 2 minutes and then restores its brightness to what it was before. Stretch your body and look over far objects in the meantime.
sudo python3 pasho.py &