Relationship with other tools

Pip Compared To easy_install

pip is meant to improve on easy_install. Some of the improvements:

  • All packages are downloaded before installation. Partially-completed installation doesn’t occur as a result.
  • Care is taken to present useful output on the console.
  • The reasons for actions are kept track of. For instance, if a package is being installed, pip keeps track of why that package was required.
  • Error messages should be useful.
  • The code is relatively concise and cohesive, making it easier to use programmatically.
  • Packages don’t have to be installed as egg archives, they can be installed flat (while keeping the egg metadata).
  • Native support for other version control systems (Git, Mercurial and Bazaar)
  • Uninstallation of packages.
  • Simple to define fixed sets of requirements and reliably reproduce a set of packages.

pip doesn’t do everything that easy_install does. Specifically:

  • It cannot install from eggs. It only installs from source. (In the future it would be good if it could install binaries from Windows .exe or .msi – binary install on other platforms is not a priority.)
  • It doesn’t understand Setuptools extras (like package[test]). This should be added eventually.
  • It is incompatible with some packages that extensively customize distutils or setuptools in their setup.py files.

pip is complementary with virtualenv, and it is encouraged that you use virtualenv to isolate your installation.

Using pip with virtualenv

pip is most nutritious when used with virtualenv. One of the reasons pip doesn’t install “multi-version” eggs is that virtualenv removes much of the need for it. Because pip is installed by virtualenv, just use path/to/my/environment/bin/pip to install things into that specific environment.

To tell pip to only run if there is a virtualenv currently activated, and to bail if not, use:

export PIP_REQUIRE_VIRTUALENV=true

Using pip with virtualenvwrapper

If you are using virtualenvwrapper, you might want pip to automatically create its virtualenvs in your $WORKON_HOME.

You can tell pip to do so by defining PIP_VIRTUALENV_BASE in your environment and setting it to the same value as that of $WORKON_HOME.

Do so by adding the line:

export PIP_VIRTUALENV_BASE=$WORKON_HOME

in your .bashrc under the line starting with export WORKON_HOME.

Using pip with buildout

If you are using zc.buildout you should look at gp.recipe.pip as an option to use pip and virtualenv in your buildouts.

Using pip with the “user scheme”

With Python 2.6 came the “user scheme” for installation, which means that all Python distributions support an alternative install location that is specific to a user. The default location for each OS is explained in the python documentation for the site.USER_BASE variable. This mode of installation can be turned on by specifying the --user option to pip install.

Moreover, the “user scheme” can be customized by setting the PYTHONUSERBASE environment variable, which updates the value of site.USER_BASE.

To install “somepackage” into an environment with site.USER_BASE customized to ‘/myappenv’, do the following:

export PYTHONUSERBASE=/myappenv
pip install --user somepackage

Command line completion

pip comes with support for command line completion in bash and zsh and allows you tab complete commands and options. To enable it you simply need copy the required shell script to the your shell startup file (e.g. .profile or .zprofile) by running the special completion command, e.g. for bash:

$ pip completion --bash >> ~/.profile

And for zsh:

$ pip completion --zsh >> ~/.zprofile

Alternatively, you can use the result of the completion command directly with the eval function of you shell, e.g. by adding:

eval "`pip completion --bash`"

to your startup file.