python on Mac

Lou Pecora pecora at
Thu Aug 28 16:18:41 CEST 2008

In article <mailman.122.1219898898.3487.python-list at>,
 luca.ciciriello at wrote:

> Hi All.
> I'm really new in the python world, so, sorry if my question is particulary
> stupid.
> I've just installed on my system (Mac OS X 10.4 PPC) the python version
> 2.5.2 and all works fine.
> My next step is to install the version 3.0 (when available). I've read
> somewhere that this version will break the backward compatibility with the
> 2.x series. I know that several Mac apps (such as Xcode developement
> environment) use python for its internal functionalities. Now, my question
> is: what will appen to the Mac apps if I install the version 3.0 of python?
> Is it safe to install this version without to compromise the behaviour of
> the system?
> Thanks in advance for any answer and, again, sorry if my question is
> particulary stupid, I will learn with time.
> Luca.

The standard Python installs that I have put the new python in the 
directory /Library/Frameworks/Python.framework/Versions/Current/   and 
the additional packages in some subdirectory of that one.

The Apple installed Python is in 

DO NOT TOUCH that one.  Just leave it alone.  You can set your 
.bash_profile path to make sure your Python is used when you run your 
scripts.  This shouldn't affect the Apple Python.  Basically, the 
directories /usr/local/:/usr/local/bin/ should come *before* the system 
/bin directories.  So your .bash_profile should have something like this 
line in it:

export PATH

Bottom line:  your installs and Apples' Python are separate and that's 
how it should be.  

Hope that helps.  Others: please correct if I am wrong. Thanks.

-- Lou Pecora

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