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[Python-Dev] Support the /usr/bin/python2 symlink upstream

Guido van Rossum guido at python.org
Tue Mar 1 23:06:07 CET 2011 
On Tue, Mar 1, 2011 at 1:26 PM, Eric Smith <eric at trueblade.com> wrote:
> On 3/1/2011 4:19 PM, Kerrick Staley wrote:
>>
>> Hello,
>> There is a need for the default Python2 install to place a symlink at
>> /usr/bin/python2 that points to /usr/bin/python, or for the
>> documentation to recommend that packagers ensure that python2 is
>> defined. Also, all documentation should be changed to recommend that
>> "#!/usr/bin/env python2" be used as the shebang for Python 2 scripts.
>> This is needed because some distributions (Arch Linux, in particular),
>> point /usr/bin/python to /usr/bin/python3, while others (including
>> Slackware, Debian, and the BSDs, probably more) do not even define the
>> python2 command. This means that a script has no way of achieving
>> cross-platform compatibility. The point at which many distributions
>> begin to alias /usr/bin/python to /usr/bin/python3 is due soon, and for
>> the next couple of years, it would be best to use a python2 or python3
>> shebang in all scripts, making no assumptions about plain python, which
>> should only be invoked interactively. This email from about 3 years ago
>> seems relevant: :
>> http://mail.python.org/pipermail/python-3000/2008-March/012421.html
>> Again, this issue needs to be addressed by the Python developers
>> themselves so that different *nix distributions will handle it
>> consistently, allowing Python scripts to continue to be cross-platform.
>>
>
> I believe we agreed at the language summit last year (or maybe even the year
> before) that "python" would always be python2.x, and "python3" would be
> python3.x.
>
> And by "always" we indeed meant forever. To do otherwise would break scripts
> even many, many years from now.

Unfortunately distros are not following these guidelines. As long as
we still have the pythonX.Y links I think it's better to have
"python2", "python3" and "python" than total anarchy.

-- 
--Guido van Rossum (python.org/~guido)
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