Why Ubuntu doesn’t support certain form of shebang for Python?

[Scott Kitterman]

On Tuesday, November 11, 2014 13:04:38 Rodney Dawes wrote:
> On Tue, 2014-11-11 at 18:02 +0100, GatoLoko wrote:
> > Since different distributions and unix systems may have different paths,
> > you may want to use the env utility in a shebang like "#!/usr/bin/env
> > python2".
> 
> Using /usr/bin/env will cause problems in certain conditions, such as
> when running under a virtualenv and other such environments.
> 
> Also, for python 2.x scripts, you should always use /usr/bin/python, and
> if python3 is required, /usr/bin/python3. There is no guarantee that
> "python2" will be a valid command.

The problem is that one Linux distro went insane and pointed /usr/bin/python 
at a python3 version, which is the only reason the PEP creating 
/usr/bin/python2 exists, so thanks to them there is no common shebang one can 
be sure will always work.  /usr/bin/python works fine everywhere but one 
distro, so that's what I'd use too.  /usr/bin/env python{2} is fine for 
developer oriented packages where they may want to override the default python 
version in some contained environment, but risky for things that are part of 
an actual system.

Scott K