git ls-files --ignored and ignored directory

I would like to use git ls-files to show all the ignored files, including directory.

As an example of setup:

mkdir /tmp/git && cd /tmp/git git init mkdir a b touch a/a touch b/b cat >.gitignore << EOF a/ b/* EOF

Then if I do: $ git ls-files --exclude-standard --ignored --others b/b $ git ls-files --exclude-standard --ignored --others --directory a/

In the first case I was expecting a/a b/b and in the second case a/ b/

Is there a way to get the behavior I'd like? Thanks!