This package will install a small Python script wich runs to listen for a GPIO signal to start a shutdown sequence. Shutdown steps can be defined in form of multiple *.sh scripts inside /usr/local/bin/pishutdownbutton.d/ directory.
native:# dpkg-deb --build pishutdownbutton_1.0-2
docker:# docker run -it -v $PWD:/mnt --workdir /mnt debian dpkg-deb --build pishutdownbutton_1.0-2
sudo dpkg -i pishutdownbutton_1.0-2.deb
systemctl start pishutdownbutton
systemctl stop pishutdownbutton