I'm unsure if this is a bug or a feature of diff, but certainly it was unexpected to me that diff doesn't account for an empty directory or file:
$ diff --version $ diff (GNU diffutils) 3.0 Packaged by Gentoo (3.0) $ mkdir a/c -p $ mkdir b/c -p $ touch b/c/emptyfile $ diff -urN a b One might argue that diff isn't exactly tar. But when generating a patch you sometimes need to create empty directories, empty files or both.
