Demonstration how the env parameter of subprocess.Popen has no effect when using sudo.

foo/run.py executes foo/runme with a changed PYTHONPATH so that foo/runme is able to import from bar.

Run it with:

cd foo
python3 run.py

Example output:

$ python3 run.py

Executing ['/home/fonfon/code/popen/foo/runme']:
Path of barfile.py: /home/fonfon/code/popen/bar/barfile.py

Executing ['sudo', '-E', '/home/fonfon/code/popen/foo/runme']:
Path of barfile.py: ImportError