document how to disable fixers

Doc/library/2to3.rst

@@ -53,13 +53,17 @@ After transformation, :file:`example.py` looks like this::
 Comments and and exact indentation are preserved throughout the translation
 process.
 
-By default, 2to3 runs a set of predefined fixers.  The :option:`-l` flag
-lists all avaible fixers.  An explicit set of fixers to run can be given by use
-of the :option:`-f` flag.  The following example runs only the ``imports`` and
-``has_key`` fixers::
+By default, 2to3 runs a set of predefined fixers.  The :option:`-l` flag lists
+all avaible fixers.  An explicit set of fixers to run can be given with
+:option:`-f`.  Likewise the :option:`-x` explicitly disables a fixer.  The
+following example runs only the ``imports`` and ``has_key`` fixers::
 
    $ 2to3 -f imports -f has_key example.py
 
+This command runs every fixer except the ``apply`` fixer::
+
+   $ 2to3 -x apply example.py
+
 Some fixers are *explicit*, meaning they aren't run be default and must be
 listed on the command line to be run.  Here, in addition to the default fixers,
 the ``idioms`` fixer is run::
@@ -78,8 +82,8 @@ flag.  Note that *only* doctests will be refactored.  This also doesn't require
 the module to be valid Python.  For example, doctest like examples in a reST
 document could also be refactored with this option.
 
-The :option:`-v` option enables the output of more information on the
-translation process.
+The :option:`-v` option enables output of more information on the translation
+process.
 
 When the :option:`-p` is passed, 2to3 treats ``print`` as a function instead of
 a statement.  This is useful when ``from __future__ import print_function`` is