running a .py file, giving it arguments and waiting for its return values

Question

Just like the title says...

Example: I have a file called copy.py. That file wants a path to a file/folder which it will move to another directory and will then return "done" if it successfully moved the file. For some reason I have to run my copy.py file from another python program (it's not given that both files are in the same directory) and wait for copy.py to finish its actions. When it is finished, it should tell me "done" or, let's say, "error", so I know if it actually was successful or not.

Please answer in a way a python beginner can understand...

Answer 1

Often, you can just import the module and call its functionality, but if it's a stand-alone program that expects command-line arguments, etc., then you may want to separate the command-line handling from the functional part of the code, so that you can import and call it as I suggested at the beginning.

Failing that, just treat it like another program:

with os.popen('python copy.py {0} {1}'.format(src, dst)) as copy:
    output = copy.readlines()
    if 'error' in output:
        # Oops...