IMO either write pure POSIX shell (no BASHisms or assuming external programs not guaranteed by POSIX exist, no assuming FHS paths are in use, etc) or require a

IMO either write pure POSIX shell (no BASHisms or assuming external programs not guaranteed by POSIX exist, no assuming FHS paths are in use, etc) or require a specific shell and set of dependencies. Check for that at the start, exit with error if things aren't found. Scripts and programs will always get run in unsupported (broken) environments. If your program can't exit with a clear error in such a situation, it's not very portable. Personally I tend to use the multi-line nix-shell shebang: #! /usr/bin/env nix-shell #! nix-shell -i SHELL -p DEPENDENCIES #! nix-shell -I nixpkgs=NIXPKGS_TARBALL_URL If you want `bash` as your shell, then `bash` goes in the SHELL location and as one of the DEPENDENCIES. If you want GNU coreutils that goes in DEPENDENCIES. Etc. The last line is optional, it pins the versions of all the dependencies you want. This also works for Python scripts.