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default python os x

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  default python os x Uwe Rangs <uwe.rangs@fernuni-hagen.de> - 2013-08-19 22:14 +0200
    Re: default python os x Uwe Rangs <uwe.rangs@fernuni-hagen.de> - 2013-08-19 22:24 +0200
      Re: default python os x Steven D'Aprano <steve@pearwood.info> - 2013-08-20 05:39 +0000
        Re: default python os x Uwe Rangs <uwe.rangs@fernuni-hagen.de> - 2013-08-20 09:01 +0200
          Re: default python os x Cameron Simpson <cs@zip.com.au> - 2013-08-21 20:22 +1000
    Re: default python os x Joel Goldstick <joel.goldstick@gmail.com> - 2013-08-19 16:46 -0400

#52704 — default python os x

Hello,

how can I change the default version of python with os x 10.7.

Thanks,
Uwe

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#52706

My workflow at the moment is to set a link:
mv python python_old
ln -s /usr/local/bin/python3.2 python

But is this a good idea?

-- Uwe

On 2013-08-19 20:14:04 +0000, Uwe Rangs said:

> Hello,
> 
> how can I change the default version of python with os x 10.7.
> 
> Thanks,
> Uwe

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#52714

On Mon, 19 Aug 2013 22:24:46 +0200, Uwe Rangs wrote:

> My workflow at the moment is to set a link: mv python python_old
> ln -s /usr/local/bin/python3.2 python
> 
> But is this a good idea?


You should never change the system Python, since that runs the risk of 
breaking system tools that expect a particular version. If there are any 
system tools that run "python", they may break.

Instead, set a personal alias. For example, in my ~/.bashrc 
file, I have the following:


export PYTHONPATH="/home/steve/python/:/home/steve/python/utilities"
export PYTHONSTARTUP=/home/steve/python/utilities/startup.py
alias python=python2.7
alias python3=python3.3
alias python1.5='env -u PYTHONSTARTUP python1.5'
alias python2.0='env -u PYTHONSTARTUP python2.0'
alias python2.1='env -u PYTHONSTARTUP python2.1'
alias python2.2='env -u PYTHONSTARTUP python2.2'
alias python2.3='env -u PYTHONSTARTUP python2.3'
alias python3.4="env -u PYTHONPATH ~/python/cpython/python"


So, for me, and me alone, typing "python" refers to Python 2.7 instead of 
the system Python, which happens to be 2.4 on my server and 2.6 on my 
laptop. "python1.5" etc unsets the startup file environment variable, 
since my startup file assumes 2.4 or better. "python3.4" points to a 
local copy in my home directory. Otherwise, python3.3, python3.2, etc. 
work as expected.


-- 
Steven

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#52721

Ah, I see. Thank you!

On 2013-08-20 05:39:56 +0000, Steven D'Aprano said:

> On Mon, 19 Aug 2013 22:24:46 +0200, Uwe Rangs wrote:
> 
>> My workflow at the moment is to set a link: mv python python_old
>> ln -s /usr/local/bin/python3.2 python
>> 
>> But is this a good idea?
> 
> 
> You should never change the system Python, since that runs the risk of
> breaking system tools that expect a particular version. If there are any
> system tools that run "python", they may break.
> 
> Instead, set a personal alias. For example, in my ~/.bashrc
> file, I have the following:
> 
> 
> export PYTHONPATH="/home/steve/python/:/home/steve/python/utilities"
> export PYTHONSTARTUP=/home/steve/python/utilities/startup.py
> alias python=python2.7
> alias python3=python3.3
> alias python1.5='env -u PYTHONSTARTUP python1.5'
> alias python2.0='env -u PYTHONSTARTUP python2.0'
> alias python2.1='env -u PYTHONSTARTUP python2.1'
> alias python2.2='env -u PYTHONSTARTUP python2.2'
> alias python2.3='env -u PYTHONSTARTUP python2.3'
> alias python3.4="env -u PYTHONPATH ~/python/cpython/python"
> 
> 
> So, for me, and me alone, typing "python" refers to Python 2.7 instead of
> the system Python, which happens to be 2.4 on my server and 2.6 on my
> laptop. "python1.5" etc unsets the startup file environment variable,
> since my startup file assumes 2.4 or better. "python3.4" points to a
> local copy in my home directory. Otherwise, python3.3, python3.2, etc.
> work as expected.

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#52762

On 20Aug2013 09:01, Uwe Rangs <uwe.rangs@fernuni-hagen.de> wrote:
| Ah, I see. Thank you!

Please don't top post. Thanks.

| On 2013-08-20 05:39:56 +0000, Steven D'Aprano said:
| >alias python1.5='env -u PYTHONSTARTUP python1.5'

I should point out that -u is a GNU env feature. It is not portable,
and in particular OSX "env" does not have it.

A shell function can do the same though:

  py20() {
    ( unset PYTHONSTARTUP
      exec python2.0 ${1+"$@"}
    )
  }

I've said py20 instead of python2.0 primarily because bash is a
bit... picky about function names and rejected the ".".

Cheers,
-- 
Cameron Simpson <cs@zip.com.au>

But pessimism IS realism!       - D.L.Bahr

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#52707

On Mon, Aug 19, 2013 at 4:14 PM, Uwe Rangs <uwe.rangs@fernuni-hagen.de> wrote:
> Hello,
>
> how can I change the default version of python with os x 10.7.
>
> Thanks,
> Uwe
>
> --
> http://mail.python.org/mailman/listinfo/python-list


You might want to look at this:

http://stackoverflow.com/questions/5846167/how-to-change-default-python-version
-- 
Joel Goldstick
http://joelgoldstick.com

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