$ git grep -Ovim # but not -O vim
-BTW, there is a difference between running ``git grep -O`` and ``git
-grep -Oless`` - in the latter case ``git grep`` passes ``+/pattern``
-option to ``less``.
+BTW, if git is instructed to use ``less`` as the pager (i.e., if pager
+is not configured in git at all it uses ``less`` by default, or if it
+gets ``less`` from PAGER environment variable, or if it was configured
+with ``git config --global core.pager less``, or ``less`` is used in
+the command ``git grep -Oless``) ``git grep`` passes ``+/$pattern``
+option to ``less`` which is quite convenient.
bash/zsh completion