pip

Overview of the steps and commands associated with virtualenv and pip.

$ sudo easy_install pip
$ sudo pip install virtualenv
$ sudo pip install virtualenvwrapper # (or virtualenv_wrapper)
$ WORKON_HOME=$HOME/.virtualenvs
$ PIP_VIRTUALENV_BASE=$WORKON_HOME
$ source /usr/local/bin/virtualenvwrapper_bashrc
$ mkvirtualenv projectname
$ easy_install pip
$ pip install tornado # NOTICE: no sudo!

Once you've created the virtualenv 'unscattered' you will now have a full python environment installed in:
   $HOME/.virtualenv/unscattered

Python packages are now installed in:
   $HOME/.virtualenv/unscattered/lib/python#.#/site-packages

Use the following commands:
$ deactivate                # this leaves the virtual env
$ workon                    # list virtual environments
$ workon ${virtualenv-name} # enter the specific virtualenv