Installing Python 3.0 on Cygwin

Question

The Question

What is the correct way to install Python 3.0 alongside Python 2.x using Cygwin?

Notes

I already have a working copy of Cygwin, and Python 2.x is installed within Cygwin (/lib/python2.x, not c:\python2.x).

Also, I would like to be able to call python 3 separately (and only intentionally) by leaving python pointing to Python 2.x to preserve existing dependencies. I would like to use python30 or some alternative.

Any pointers to guides on the subject would be much appreciated. I cannot seem to find one either at the cygwin site or python.org.

Answer 1

As of yesterday (Wed 25 July 2012), Python 3.2.3 is included in the standard Cygwin installer. Just run Cygwin's setup.exe again (download it from cygwin.com again if you need to), and you should be able to select and install it like any other package.

This will install as python3, leaving any existing 2.x install in place:

$ python -V
Python 2.6.8
$ python3 -V
Python 3.2.3
$ ls -l $(which python) $(which python3)
lrwxrwxrwx 1 me Domain Users 13 Jun 21 15:12 /usr/bin/python -> python2.6.exe
lrwxrwxrwx 1 me root         14 Jul 26 10:56 /usr/bin/python3 -> python3.2m.exe

Answer 2

The standard make install target of the Python 3.0 sources doesn't install a python binary. Instead, make install prints at the end

* Note: not installed as 'python'.
* Use 'make fullinstall' to install as 'python'.
* However, 'make fullinstall' is discouraged,
* as it will clobber your Python 2.x installation.

So don't worry.

If you easily want to remove the entire installation, do something like configure --prefix=/usr/local/py3