On Thu, 29 Aug 2019 at 17:56, Robert Moskowitz <rgm@htt-consult.com> wrote:


On 8/29/19 4:41 PM, Cameron Simpson wrote:
> On 29Aug2019 16:20, Robert Moskowitz <rgm@htt-consult.com> wrote:
>> On 8/29/19 4:14 PM, Tom Horsley wrote:
>>> On Thu, 29 Aug 2019 16:02:25 -0400
>>> Robert Moskowitz wrote:
>>>> Do I need to do anything, or will this be self-correcting come the
>>>> new year?
>>> I forget where (maybe in redhat rather than fedora), but some
>>> distro has utterly removed /usr/bin/python all it has now
>>> is /usr/bin/python2 or /usr/bin/python3 and your scripts need
>>> to explicitly refer to one or the other.
>>
>> So no more just pip.  It is pip3.
>>
>> xml2rfc claims it works just fine with either.
>
> These days the advice is to use:
>
>  python -m pip
>
> adjusting "python" as desired. That way you get the pip that affects
> your intended python install.

Which goes really nicely into the next question.

It seems the default right now is 2.7:

$ python --version
Python 2.7.16

Will this automagically change on Jan 1, 2020?

$ python3 --version
Python 3.7.4

The python people recommended keeping python for python 2, and using python3 for
python 3.  Unfortunately, at least one prominent python package, anaconda, uses
python for python 3.
 
Is there a way to get it changed now and see what is in trouble (though
there is very little python that I know I am using).

https://python-3-for-scientists.readthedocs.io/en/latest/ has lots of useful
information.

Python packages that are actively maintained are being converted to use
python 3.  In many cases this can be done in a way that allows the code
to use either python 2 or python3.  The problem comes with older, unmaintained
packages.  Often these are orphaned because there is something better
you should be using, for some definition of "better".  The major reason for
python 3 was to better support unicode, so linux distributions with
global reach needed python 3.

There has been a global shift in the importance of Chinese, Korean, and
Japanese (CJK) language customers to Western vendors.  Python 3 is
one consequence, but we also have lualatex and unicode fonts in place
of Postscript. Western companies selling in CJK markets need unicode
for web sites, manuals, and the software they distribute. 

A while ago I compared lists of python 2 and python 3 packages for
Ubuntu.  The python 2 list was much longer, but there were only a
few python 2 packages installed that did not have python 3 versions.
You might find a similar exercise useful for Fedora.

--
George N. White III