How to link home brew python version and set it as default

Question

I just switched from MacPorts to HomeBrew. After installing all the required XCode versions and other software I tried installing python using homebrew: I think it successfu

Answer 1

On OS X High Sierra, I had to do this:

sudo install -d -o $(whoami) -g admin /usr/local/Frameworks
brew uninstall --ignore-dependencies python
brew install python
python --version # should work, returns 2.7, which is a Python thing (it's weird, but ok)

credit to https://gist.github.com/irazasyed/7732946#gistcomment-2235469

I think it's better than recursively chowning the /usr/local dir, but that may solve other problems ;)

Answer 2

In the Terminal, type:

brew link python

Answer 3

The problem with me is that I have so many different versions of python, so it opens up a different python3.7 even after I did brew link. I did the following additional steps to make it default after linking

First, open up the document setting up the path of python

 nano ~/.bash_profile

Then something like this shows up:

# Setting PATH for Python 3.7
# The original version is saved in .bash_profile.pysave
PATH="/Library/Frameworks/Python.framework/Versions/3.7/bin:${PATH}"
export PATH

# Setting PATH for Python 3.6
# The original version is saved in .bash_profile.pysave
PATH="/Library/Frameworks/Python.framework/Versions/3.6/bin:${PATH}"
export PATH

The thing here is that my Python for brew framework is not in the Library Folder!! So I changed the framework for python 3.7, which looks like follows in my system

# Setting PATH for Python 3.7
# The original version is saved in .bash_profile.pysave
PATH="/usr/local/Frameworks/Python.framework/Versions/3.7/bin:${PATH}"
export PATH

Change and save the file. Restart the computer, and typing in python3.7, I get the python I installed for brew.

Not sure if my case is applicable to everyone, but worth a try. Not sure if the framework path is the same for everyone, please made sure before trying out.

Answer 4

After installing python3 with brew install python3 I was getting the error:

Error: An unexpected error occurred during the `brew link` step
The formula built, but is not symlinked into /usr/local
Permission denied @ dir_s_mkdir - /usr/local/Frameworks
Error: Permission denied @ dir_s_mkdir - /usr/local/Frameworks

After typing brew link python3 the error was:

Linking /usr/local/Cellar/python/3.6.4_3... Error: Permission denied @ dir_s_mkdir - /usr/local/Frameworks

To solve the problem:

sudo mkdir -p /usr/local/Frameworks
sudo chown -R $(whoami) /usr/local/*
brew link python3

After this, I could open python3 by typing python3

Answer 5

I think you have to be precise with which version you want to link with the command brew link python like:

brew link python 3

It will give you an error like that:

Linking /usr/local/Cellar/python3/3.5.2... 
Error: Could not symlink bin/2to3-3.5
Target /usr/local/bin/2to3-3.5
already exists. 

You may want to remove it:

rm '/usr/local/bin/2to3-3.5'

To force the link and overwrite all conflicting files:

brew link --overwrite python3

To list all files that would be deleted:

brew link --overwrite --dry-run python3

but you have to copy/paste the command to force the link which is:

brew link --overwrite python3

I think that you must have the version (the newer) installed.

Answer 6

If you used

brew install python

before 'unlink' you got

brew info python
/usr/local/Cellar/python/2.7.11

python -V
Python 2.7.10

so do

brew unlink python && brew link python

and open a new terminal shell

python -V
Python 2.7.11