Question

I have 2 versions of python installed on windows, 2.7.3 and 3.3. Some of my scripts are 2.x and some 3.x. Is there an easy way when executing these scripts from a command line to direct them to the appropriate interpreter?

Answer 1

Note: For Windows use the new Windows Python launcher (available with Python 3.3 and downloadable here for earlier releases) which recognizes Unix shell shebangs. You can read about it here.

Most Linux distributions will create python2 and python3 aliases for the installed Python 2.x and Python 3.x interpreter (if not you can just create the symbolic links yourself anywhere on your $PATH, the env command will take care of finding them), so you should just need to set the appropriate interpreter as the first line of your script:

#!/usr/bin/env python2

or

#!/usr/bin/env python3

This will direct the shell to use the appropriate interpreter, if you set the script files to be executable and just invoke them directly on the shell. E.g.:

$ chmod +x script.py
$ ./script.py