macos - How to make Mac OS use the python installed by Homebrew

Question

I have searched online for a while for this question, and what I have done so far is

1. installed python32 in homebrew

2. changed my .bash_profile and added the following line to it:

export PATH=/usr/local/bin:/usr/local/sbin:~/bin:$PATH

but when I close the terminal and start again, I type 'which python', it still prints:

/usr/bin/python

and type 'python --version' still got:

Python 2.7.2

I also tried the following instruction:

brew link --overwrite python

or try to remove python installed by homebrew by running this instruction:

brew remove python

but both of the above two instructions lead to this error:

Error: No such keg: /usr/local/Cellar/python

can anybody help, thanks

Answer 1

If you want to install Python 3 using Homebrew:

$ brew install python3
==> Downloading http://python.org/ftp/python/3.3.0/Python-3.3.0.tar.bz2
Already downloaded: /Library/Caches/Homebrew/python3-3.3.0.tar.bz2
==> ./configure --prefix=/usr/local/Cellar/python3/3.3.0 --enable-ipv6 --datarootdir=/usr/local/Cell
==> make
==> make install PYTHONAPPSDIR=/usr/local/Cellar/python3/3.3.0
==> make frameworkinstallextras PYTHONAPPSDIR=/usr/local/Cellar/python3/3.3.0/share/python3
==> Downloading https://pypi.python.org/packages/source/d/distribute/distribute-0.6.35.tar.gz
Already downloaded: /Library/Caches/Homebrew/distribute-0.6.35.tar.gz
==> /usr/local/Cellar/python3/3.3.0/bin/python3.3 -s setup.py install --force --verbose --install-li
==> Downloading https://pypi.python.org/packages/source/p/pip/pip-1.3.1.tar.gz
Already downloaded: /Library/Caches/Homebrew/pip-1.3.1.tar.gz
==> /usr/local/Cellar/python3/3.3.0/bin/python3.3 -s setup.py install --force --verbose --install-li
==> Caveats
Homebrew's Python3 framework
  /usr/local/Cellar/python3/3.3.0/Frameworks/Python.framework

Distribute and Pip have been installed. To update them
  pip3 install --upgrade distribute
  pip3 install --upgrade pip

To symlink "Idle 3" and the "Python Launcher 3" to ~/Applications
  `brew linkapps`

You can install Python packages with
  `pip3 install <your_favorite_package>`

They will install into the site-package directory
 /usr/local/lib/python3.3/site-packages
Executable python scripts will be put in:
 /usr/local/share/python3
so you may want to put "/usr/local/share/python3" in your PATH, too.

See: https://github.com/mxcl/homebrew/wiki/Homebrew-and-Python

Once installed update your system PATH variable, add the next line to ~/.bash_profile

export PATH=/usr/local/bin:/usr/local/sbin:~/bin:$PATH

And then:

$ source ~/.bash_profile

Now launch Python:

$ python3
Python 3.3.0 (default, Mar 26 2013, 10:01:40) 
[GCC 4.2.1 Compatible Apple LLVM 4.2 (clang-425.0.27)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>>

You can check python3 path:

$ which python3
/usr/local/bin/python3