What I've tried:
bash scripts/shell/test.shsh scripts/shell/test.sh
These were the results:
The term 'bash' is not recognized...
The term 'sh' is not recognized...
This may sound daft, but if you are in a Powershell shell how will that shell know where to find the bash or sh interpreter? Is it already defined in the environment?
In my opinion you're going to have to tell the Powershell terminal where it should find the bash/sh interpreter, i.e. call bash it with the full pathname
sh works on Git bash. Is there a way to add the PATH for the sh command that Git bash uses to Windows environment variables? So that it is also accessible from the PowerShell CLI?