+ * A magic pathspec ":/" tells a command that limits its operation to
+ the current directory when ran from a subdirectory to work on the
+ entire working tree. In general, ":/path/to/file" would be relative
+ to the root of the working tree hierarchy.
+
+ After "git reset --hard; edit Makefile; cd t/", "git add -u" would
+ be a no-op, but "git add -u :/" would add the updated contents of
+ the Makefile at the top level. If you want to name a path in the
+ current subdirectory whose unusual name begins with ":/", you can
+ name it by "./:/that/path" or by "\:/that/path".
+