After year and a bit, i knew it was all wrong and too complex, so it is oneliner now in one single file.
installation on Debian:
sudo curl -L \
https://github.com/pkristian/mishell.sh/releases/download/v0.90/mishell.sh \
-o /usr/local/bin/mishell.sh
sudo chmod +x /usr/local/bin/mishell.sh
bash mishell.sh --version .