I understand, but is it at least possible to officially recommend that python, python2, and python3 all exist, that distributions point python to python2, and that scripts specify which of python2 and python3 they are using? This would create a redundant system that doesn't avoids problems even if distributions do decide to ignore the second point. If not, can someone point me to official documentation that recommends that python always invoke Python2, so that I can take the case up with the Arch developers? Thanks, Kerrick Staley On Tue, Mar 1, 2011 at 3:26 PM, Eric Smith <eric@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.
Eric. _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/mail%40kerrickstaley.com