Bash controlled Raspberry Pi 3B relay hat

If you would like to control some electrical devices by switching them on and off then one possiblity is to use Rasberry Pi relay hat. It is from Waveshare/Botland and it fits on top of your Raspberry Pi. It contains 3 relays controllers with screw connectors. Once you wire your devices you can even put it within DIN box like this one below. Be sure to be careful inserting micro SD card as this box fits tight and you can easily break card apart like I once did. In order to control relay connectors first you export pins: Then you