MAC terminal shell sh - file directory not recognized

The question mixes references to the POSIX shell sh and to zsh, which are disparate shells.

Which error are you encountering with the POSIX shell sh?

What is the script invocation command?

Which shell is specified in the shebang within the script?

If it's bash, the built-in version of bash on macOS is very old. Ancient.

For bash, using an add-on bash and the shebang #!/usr/bin/env bash might help things work better.

Might want to check with the package maintainers, too. Have they tested on macOS?

If you want us to look at the script and its error, you'll need to post that.

If you are implementing an install, you should be very careful about messing with a user's personalized shell initialization files.

First, because even if you know the shell the user is using, you cannot be sure with initialization file they are using. For example, the bash shell has .bash_profile, .bash_login and .profile. It will ONLY use one of them. If the user was using .profile, and you created .bash_profile, you would screw up the user's expected environment.

Also if you decide you are going to modify the PATH environment variable, where you choose to add that change may conflict with where the user is modifying PATH, and you might break the user's environment.

Anything you install using any shell, should NOT assume anything about the user's environment. And should if possible specify full path names for commands, so you do not accidentally invoke a different flavor of a command because the user has their own customizations.

Finally, when invoking sh via an install utility it may not even look at the user's shell initialization files, so anything you expect to find in a shell initialization file may not be present during your installation invocation of sh