Whilst looking through the PR's currently open, I came across one where
a person was attempting to chown a file to a user where the username was
made up of a ".".  Easy to deal with ?  Maybe.

Consider that a username might be "foo.bar", "foo", "bar" and a group
name to match each of those.

If I do "chown foo.bar /tmp/foryou" what should happen ?

Is the best option, in this case, to simply bail out becase the user
is not being clear about what they want to do ?

Darren