virtualenvwrapper is a set of extensions to Ian Bicking’s virtualenv tool. The extensions include wrappers for creating and deleting virtual environments and otherwise managing your development workflow, making it easier to work on more than one project at a time without introducing conflicts in their dependencies.

The best way to explain the features virtualenvwrapper gives you is to show it in use.

First, some initialization steps. Most of this only needs to be done one time. You will want to add the command to source /usr/local/bin/virtualenvwrapper.sh to your shell startup file, changing the path to virtualenvwrapper.sh depending on where it was installed by pip or your package manager.

$ pip install virtualenvwrapper ... $ export WORKON_HOME=~/Envs $ mkdir -p $WORKON_HOME $ source /usr/local/bin/virtualenvwrapper.sh $ mkvirtualenv env1 Installing setuptools.......................................... .................................................... .................................................... ...............................done. virtualenvwrapper.user_scripts Creating /Users/dhellmann/Envs/env1/bin/predeactivate virtualenvwrapper.user_scripts Creating /Users/dhellmann/Envs/env1/bin/postdeactivate virtualenvwrapper.user_scripts Creating /Users/dhellmann/Envs/env1/bin/preactivate virtualenvwrapper.user_scripts Creating /Users/dhellmann/Envs/env1/bin/postactivate New python executable in env1/bin/python (env1)$ ls $WORKON_HOME env1 hook.log

Now we can install some software into the environment.

(env1)$ pip install django Downloading/unpacking django Downloading Django-1.1.1.tar.gz (5.6Mb): 5.6Mb downloaded Running setup.py egg_info for package django Installing collected packages: django Running setup.py install for django changing mode of build/scripts-2.6/django-admin.py from 644 to 755 changing mode of /Users/dhellmann/Envs/env1/bin/django-admin.py to 755 Successfully installed django

We can see the new package with lssitepackages :

(env1)$ lssitepackages Django-1.1.1-py2.6.egg-info easy-install.pth setuptools-0.6.10-py2.6.egg pip-0.6.3-py2.6.egg django setuptools.pth

Of course we are not limited to a single virtualenv:

(env1)$ ls $WORKON_HOME env1 hook.log (env1)$ mkvirtualenv env2 Installing setuptools............................... .................................................... .................................................... ........... ...............................done. virtualenvwrapper.user_scripts Creating /Users/dhellmann/Envs/env2/bin/predeactivate virtualenvwrapper.user_scripts Creating /Users/dhellmann/Envs/env2/bin/postdeactivate virtualenvwrapper.user_scripts Creating /Users/dhellmann/Envs/env2/bin/preactivate virtualenvwrapper.user_scripts Creating /Users/dhellmann/Envs/env2/bin/postactivate New python executable in env2/bin/python (env2)$ ls $WORKON_HOME env1 env2 hook.log

Switch between environments with workon :

(env2)$ workon env1 (env1)$ echo $VIRTUAL_ENV /Users/dhellmann/Envs/env1 (env1)$

The workon command also includes tab completion for the environment names, and invokes customization scripts as an environment is activated or deactivated (see Per-User Customization).

(env1)$ echo 'cd $VIRTUAL_ENV' >> $WORKON_HOME/postactivate (env1)$ workon env2 (env2)$ pwd /Users/dhellmann/Envs/env2

postmkvirtualenv is run when a new environment is created, letting you automatically install commonly-used tools.

(env2)$ echo 'pip install sphinx' >> $WORKON_HOME/postmkvirtualenv (env3)$ mkvirtualenv env3 New python executable in env3/bin/python Installing setuptools............................... .................................................... .................................................... ........... ...............................done. virtualenvwrapper.user_scripts Creating /Users/dhellmann/Envs/env3/bin/predeactivate virtualenvwrapper.user_scripts Creating /Users/dhellmann/Envs/env3/bin/postdeactivate virtualenvwrapper.user_scripts Creating /Users/dhellmann/Envs/env3/bin/preactivate virtualenvwrapper.user_scripts Creating /Users/dhellmann/Envs/env3/bin/postactivate Downloading/unpacking sphinx Downloading Sphinx-0.6.5.tar.gz (972Kb): 972Kb downloaded Running setup.py egg_info for package sphinx no previously-included directories found matching 'doc/_build' Downloading/unpacking Pygments>=0.8 (from sphinx) Downloading Pygments-1.3.1.tar.gz (1.1Mb): 1.1Mb downloaded Running setup.py egg_info for package Pygments Downloading/unpacking Jinja2>=2.1 (from sphinx) Downloading Jinja2-2.4.tar.gz (688Kb): 688Kb downloaded Running setup.py egg_info for package Jinja2 warning: no previously-included files matching '*' found under directory 'docs/_build/doctrees' Downloading/unpacking docutils>=0.4 (from sphinx) Downloading docutils-0.6.tar.gz (1.4Mb): 1.4Mb downloaded Running setup.py egg_info for package docutils Installing collected packages: docutils, Jinja2, Pygments, sphinx Running setup.py install for docutils Running setup.py install for Jinja2 Running setup.py install for Pygments Running setup.py install for sphinx no previously-included directories found matching 'doc/_build' Installing sphinx-build script to /Users/dhellmann/Envs/env3/bin Installing sphinx-quickstart script to /Users/dhellmann/Envs/env3/bin Installing sphinx-autogen script to /Users/dhellmann/Envs/env3/bin Successfully installed docutils Jinja2 Pygments sphinx (env3)$ (venv3)$ which sphinx-build /Users/dhellmann/Envs/env3/bin/sphinx-build

Through a combination of the existing functions defined by the core package (see Command Reference), third-party plugins (see Extending Virtualenvwrapper), and user-defined scripts (see Per-User Customization) virtualenvwrapper gives you a wide variety of opportunities to automate repetitive operations.