I need to run a python command inside a Popen. The problem is that the command NEEDS to run in python3 and I need it to be portable, which means that I can't really use the python3 alias for every situation...
I have computers where python is already the correct version, and others where the correct one is python3. I tried to insert #!/usr/bin python3 in the beginning of the file and then run as python but it didn't work.
I can't modify environment vars to change python3 to python. I would like to know if there is a way to check which one I need to use or a way to change the python3 to python ONLY inside the Popen command...
The Popen command I am trying to run is very simple and no I can't just import the file and use as a class... it needs to be ran through Popen. Also, virtualenv or similars are not an option.
subprocess.Popen(['python', 'main.py'], shell=True, universal_newlines=True)
The shebang -- the initial line showing which interpreter to use, such as #!/usr/bin/python or #!/usr/bin/python3 -- is only honored if you don't explicitly select an interpreter yourself: If you run python foo.py, the OS is invoking a specific Python interpreter and passing it foo.py as an argument (which it interprets as the name of a script it should run); whereas when you run ./foo.py, you're telling the OS itself to figure out which interpreter to use to run foo.py, which it does by looking at the shebang.
To leave it up to the operating system to select, just explicitly specify the name of your script:
subprocess.Popen(['./main.py'], universal_newlines=True)