Flesh out virtualenvs section.

Author: john2x

docs/dev/virtualenvs.rst

@@ -1,15 +1,92 @@
 Virtual Environments
 ====================
 
-.. todo:: Explain "Virtual Environments"
+A Virtual Environment, put simply, is an isolated working copy of Python which allows you to work on a specific project without worry of affecting other projects.
+
+For example, you can work on a project which requires Django 1.3 at the same time with a project which requires Django 1.0.
+
 
 virtualenv
 ----------
 
-.. todo:: Write about virtualenv
+`virtualenv <http://pypi.python.org/pypi/virtualenv>`_ is a tool to create isolated Python environments.
+
+Install it via pip::
+
+  $ pip install virtualenv
+
+Basic Usage
+~~~~~~~~~~~
+
+1. Create a virtual environment::
+
+   $ virtualenv ENVIRONMENT_NAME
+
+This creates a copy of Python in whichever directory you ran the command in, placing it in a folder named ``ENVIRONMENT_NAME``.
+
+2. To begin using the virtual environment, it needs to be activated::
+
+   $ source ENVIRONMENT_NAME/bin/activate
+
+You can then begin installing any new modules without affecting the system default Python or other virtual environments.
+
+3. If you are done working in the virtual environment for the moment, you can deactivate it::
+
+   $ deactivate
+
+This puts you back to the system's default Python interpreter with all its installed libraries.
+
+To delete a virtual environment, just delete its folder.
 
 virtualenvwrapper
 -----------------
 
-.. todo:: Write about virtualenvwrapper
+`virtualenvwrapper <http://www.doughellmann.com/projects/virtualenvwrapper/>`_ provides a set of commands which makes working with virtual environments much more pleasant. It also places all your virtual environments into one place.
+
+To install (make sure virtualenv is already installed)::
+
+  $ pip install virtualenvwrapper
+  $ export WORKON_HOME=~/Envs
+  $ source /usr/local/bin/virtualenvwrapper.sh
+
+(Full instructions `here <http://www.doughellmann.com/docs/virtualenvwrapper/#introduction>`_.)
+
+Basic Usage
+~~~~~~~~~~~
+
+1. Create a virtual environment::
+
+   $ mkvirtualenv ENVIRONMENT_NAME
+
+This creates the ``ENVIRONMENT_NAME`` folder inside ``~/Envs``. 
+
+2. Work on a virtual environment::
+
+   $ workon ENVIRONMENT_NAME
+
+**virtualenvwrapper** provides tab-completion on environment names. It really helps when you have a lot of environments and have trouble remembering their names. 
+``workon`` also deactivates whatever environment you are currently in, so you can quickly switch between environments.
+
+3. Deactivating is still the same::
+
+   $ deactivate
+
+4. To delete::
+
+   $ rmvirtualenv ENVIRONMENT_NAME
+
+Other nifty commands include:
+
+``lsvirtualenv``
+  List all of the environments.
+
+``cdvirtualenv``
+  Navigate into the directory of the currently activated virtual environment, so you can browse its ``site-packages``, for example. 
+
+``cdsitepackages``
+  Like the above, but directly into ``site-packages`` directory.
+
+``lssitepackages``
+  Shows contents of ``site-packages`` directory.
 
+Full list of commands can be found `here <http://www.doughellmann.com/docs/virtualenvwrapper/command_ref.html#managing-environments>`_.