How to use multiple versions of Python without uninstallation

Question

I am faced with a unique situation, slightly trivial but painful.

I need to use Python 2.6.6 because NLTK is not ported to Python 3 (that\'s what I could gather).

Answer 1

If you're talking about shell, as in linux, if you install python 3, you can invoke it separately with the python3 command. Python 2 is just invoked using python.

At least this is my experience with Ubuntu-like systems, I haven't used other Linux environments.

I realize this question is almost a year old, but NLTK has been ported to Python 3 (or at least that was true as of writing this).