clean: require double -f options to nuke nested git repository and work tree

diff --git a/Documentation/git-clean.txt b/Documentation/git-clean.txt
index be894af39ff6559affbf0617e4c5d8fe68c33fe8..ae8938b2de9a5930ab18a220a6e8dd90ee6db3b1 100644 (file)
--- a/Documentation/git-clean.txt
+++ b/Documentation/git-clean.txt
@@ -27,6 +27,9 @@ OPTIONS
 -------
 -d::
        Remove untracked directories in addition to untracked files.
+       If an untracked directory is managed by a different git
+       repository, it is not removed by default.  Use -f option twice
+       if you really want to remove such a directory.
 
 -f::
        If the git configuration specifies clean.requireForce as true,