Importing Local files

How can i import local file when packaging a software for nixpkgs (nix-build) such that source will recognise fetchFromGithub as well as a file in my local directory i.e (myfile.sh) needed to package the software?

You can use e.g. ${./myfile.sh} to turn a local path into a nix store path and use it in a string, which you could use in various ways in a derivation.

Can you expand a bit on what exactly you want to achieve?

It actually worked. Thank you