Running both python 2.6 and 3.1 on the same machine

Question

Hi there,

I'm currently toying with python at home and I'm planning to switch to python 3.1. The fact is that I have some script that use python 2.6 and I can't convert them since they use some module that aren't available for python 3.1 atm. So I'm considering installing python 3.1 along my python 2.6. I only found people on internet that achieve that by compiling python from source and use make altinstall instead of the classic make install. Anyway, I think compiling from source is a bit complicated. I thought running two different version of a program is easy on linux (I run fedora 11 for the record). Any hint?

Thanks for reading.

Answer 1

You're not supposed to need to run them together.

2.6 already has all of the 3.0 features. You can enable those features with from __future__ import statements.

It's much simpler run 2.6 (with some from __future__ import) until everything you need is in 3.x, then switch.

Answer 2

Download the python version you want to have as an alternative, untar it, and when you configure it, use --prefix=/my/alt/dir

Cheers

Nik

Answer 3

On my Linux system (Ubuntu Jaunty), I have Python 2.5, 2.6 and 3.0 installed, just by installing the binary (deb) packages 'python2.5', 'python2.6' and 'python3.0' using apt-get. Perhaps Fedora packages them and names them as RPMs in a similar way.

I can run the one I need from the command line just by typing e.g. python2.6. So I can also specify the one I want at the top of my script by putting e.g.:

#!/usr/bin/python2.6

Answer 4

Why do you need to use make install at all? After having done make to compile python 3.x, just move the python folder somewhere, and create a symlink to the python executable in your ~/bin directory. Add that directory to your path if it isn't already, and you'll have a working python development version ready to be used. As long as the symlink itself is not named python (I've named mine py), you'll never experience any clashes.

An added benefit is that if you want to change to a new release of python 3.x, for example if you're following the beta releases, you simply download, compile and replace the folder with the new one.

It's slightly messy, but the messiness is confined to one directory, and I find it much more convenient than thinking about altinstalls and the like.