-+
-If exactly two paths are given and at least one points outside
-the current repository, 'git diff' will compare the two files /
-directories. This behavior can be forced by --no-index.
+
+'git diff' --no-index [--options] [--] [<path>...]::
+
+ This form is to compare the given two paths on the
+ filesystem. You can omit the `--no-index` option when
+ running the command in a working tree controlled by Git and
+ at least one of the paths points outside the working tree,
+ or when running the command outside a working tree
+ controlled by Git.