Choose Python version to install egg or install side-by-side versions of site-package

Edit: Read Ned Daley's answer before reading this

1.

On my system, I have a different easy_install script for each python version:

• /usr/bin/easy_install-2.5
• /usr/bin/easy_install-2.6

The 2.6 content looks like this:

#!/System/Library/Frameworks/Python.framework/Versions/2.6/Resources/Python.app/Contents/MacOS/Python
import sys
sys.argv[0] = sys.argv[0].replace('-2.6', '')
# EASY-INSTALL-ENTRY-SCRIPT: 'setuptools==0.6c9','console_scripts','easy_install'
__requires__ = 'setuptools==0.6c9'
import sys
from pkg_resources import load_entry_point

sys.exit(
   load_entry_point('setuptools==0.6c9', 'console_scripts', 'easy_install')()
)

      

        
        
        
      

    

Now, if you don't already have these scripts on your computer, you can create them using the template above. Just change the first line to point to the correct python interpreter. Perhaps something like:

#!/sw/bin/python23

      

        
        
        
      

    

And change the third line to match the current script name; meaning if the script is called easy_install-2.3 then it should look like this:

sys.argv[0] = sys.argv[0].replace('-2.3', '')

      

        
        
        
      

    

And of course, if you are not using setuptools version 0.6c9, you will have to change that as well.

An alternative is to run easy_install script as an argument to the right python version. Like this:

$ python23 /some/path/easy_install networkx-0.36-py2.5.egg

      

        
        
        
      

    

2.

Each python version has a different site-lib, so they are independent from each other. You can install different modules and versions for different python versions.

3.

You can make the PYTHONPATH variable env to the shared directory, or add the shared directory to sys.path in your scripts. But be aware that some modules only work with certain python versions and include C code that needs to be compiled for each python version ...