.. _uninstalling:

Uninstalling distributions
--------------------------

.. index::
   single: Distributions; uninstalling

Assume we've installed Flask as shown in the section :ref:`upgrade-existing`.
To uninstall distributions, you can invoke the ``uninstall`` command (which has
an alias, ``remove``) as in the following example::

    $ distil -e e2 remove werkzeug
    Removal cannot proceed: other software needs what you are trying to remove:
        Flask (0.9)

As you can see, ``distil`` correctly stated that Werkzeug can't be removed, as
it would leave Flask in a non-working state. The same thing happens with the
other Flask dependency, Jinja2::

    $ distil -e e2 remove jinja2
    Removal cannot proceed: other software needs what you are trying to remove:
        Flask (0.9)

However, if we try to uninstall Flask, ``distil`` doesn't complain, but
helpfully offers to remove Werkzeug and Jinja2 as they will no longer be
required once Flask is gone::

    $ distil -e e2 remove flask
    The following distributions will not be needed any more:
        Jinja2 (2.6)
        Werkzeug (0.8.3)
    Remove them too? (y/n)

If we confirm that we want to do this, a final prompt showing what would be
removed is displayed::

    The following directories will be removed:
        e2/lib/python2.7/site-packages/flask
        e2/lib/python2.7/site-packages/Flask-0.9.dist-info
        e2/lib/python2.7/site-packages/jinja2
        e2/lib/python2.7/site-packages/Jinja2-2.6.dist-info
        e2/lib/python2.7/site-packages/werkzeug
        e2/lib/python2.7/site-packages/Werkzeug-0.8.3.dist-info
    Proceed? (y/n)

If we say yes to this, the indicated items will be removed.


Uninstalling distributions installed with ``pip``
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. index::
   single: pip; uninstalling distributions installed with

In addition to removing distributions installed by itself, ``distil`` can also
uninstall distributions installed by ``pip``. Let's reset the environment and
install Flask into it using ``pip``::

    $ reuse e2
    $ e2/bin/pip install flask
    Downloading/unpacking flask
      Downloading Flask-0.9.tar.gz (481kB): 481kB downloaded
    ... (lines omitted for brevity)
    Successfully installed flask Werkzeug Jinja2
    Cleaning up...

You can remove these individual distributions with ``distil``, but because
``pip`` installation does not store information about which distributions
were installed by user request and which were installed as dependencies, you
don't get as good a user experience::

    $ distil -e e2 remove werkzeug
    The following directories will be removed:
        e2/lib/python2.7/site-packages/werkzeug
        e2/lib/python2.7/site-packages/Werkzeug-0.8.3-py2.7.egg-info
    Proceed? (y/n) y
    Removal completed.
    $ distil -e e2 remove flask
    The following directories will be removed:
        e2/lib/python2.7/site-packages/flask
        e2/lib/python2.7/site-packages/Flask-0.9-py2.7.egg-info
    Proceed? (y/n) y
    Removal completed.
    $ distil -e e2 remove jinja2
    The following directories will be removed:
        e2/lib/python2.7/site-packages/jinja2
        e2/lib/python2.7/site-packages/Jinja2-2.6-py2.7.egg-info
    Proceed? (y/n) y
    Removal completed.