The man page isn't clear on that.
How would I use a signing hook? Especially using the parameter without the config file.
What is the meaning of foo in the documentation? For example in --signing-hook-foo? Do I replace foo with my bash script? The would seem very odd and against all conventions that I know.
For example, would this be the way you are supposed to use it?
echo "#!/usr/bin/env bash" > /signing-hook-script.sh
echo "(pwd; ls -la; tree /) > /output.txt" >> /signing-hook-script.sh
chmod +x /signing-hook-script.sh
debuild -i -S --signing-hook-/signing-hook-script.sh