设置默认的python 2.7。

Question

I have just installed python 2.7 using macports as:

sudo port install py27-numpy py27-scipy py27-matplotlib py27-ipython +notebook py27-pandas py27-sympy py27-nose

during the process it found some issues, mainly broken files related with py25-haslib that I managed to fix. Now it seems eveything is ok. I tested a few programs and they run as expected. Currently, I have two versions of python: 2.5 (Default, from when I worked in my former institution) and 2.7 (just installed):

which python

/usr/stsci/pyssg/Python-2.5.1/bin/python

which python2.7

/opt/local/bin/python2.7

The next move would be set the new python version 2.7 as default:

sudo port select --set python python27

sudo port select --set ipython ipython27

My question is: is there a way to go back to 2.5 in case something goes wrong?

I know a priori, nothing has to go wrong. But I have a few data reduction and analysis routines that work perfectly with the 2.5 version and I want to make sure I don´t mess up before setting the default.

Answer 1

if you want to revert, you can modify your .bash_profile or other login shell initialization to fix $PATH to not add "/Library/Frameworks/Python.framework/Versions/2.5/bin" to $PATH and/or to not have /usr/local/bin appear before /usr/bin on $PATH.

If you want to permanently remove the python.org installed version, paste the following lines up to and including the chmod into a posix- compatible shell:

tmpfile=/tmp/generate_file_list
cat <<"NOEXPAND" > "${tmpfile}"
#!/bin/sh
version="${1:-"2.5"}"
file -h /usr/local/bin/* | grep \
"symbolic link to ../../../Library/Frameworks/Python.framework/"\
"Versions/${version}" | cut -d : -f 1
echo "/Library/Frameworks/Python.framework/Versions/${version}"
echo "/Applications/Python ${version}"
set -- Applications Documentation Framework ProfileChanges \
         SystemFixes UnixTools
for package do
  echo "/Library/Receipts/Python${package}-${version}.pkg"
done
NOEXPAND
chmod  ug+x ${tmpfile}

...excripted from troubleshooting question on python website