# Original location "python" is installed (OS X pre-packaged Python 2)
$ which python
/usr/bin/python

## Install python3 from homebrew
$ brew install python
# New location where "python" is installed (brew version of Python 3)
$ which python
/usr/local/bin/python
# Associated "pip" command (auto-installed by homebrew)
$ pip

## Install python2 from homebrew
$ brew install python2
# Add homebrew python2 to the path
$ echo 'export PATH="/usr/local/opt/python@2/bin:$PATH"' >> ~/.bash_profile
# Associated "pip" command (auto-installed by homebrew)
$ pip2

## Install virtualenvwrapper
$ pip install virtualenvwrapper
# Add the virtualenv commands to the path
$ echo 'source virtualenvwrapper.sh' >> ~/.bash_profile
# Create a virtual environment
$ mkvirtualenv [-p /usr/local/bin/<pyversion>] <envname>
# List all virtual environments
$ lsvirtualenv
# Work on a particular environment
$ workon <envname>
# Exit an environment
$ deactivate
# Remove an environment
$ rmvirtualenv <envname>
# Turn on site packages while inside environment
$ toggleglobalsitepackages