$ corelist File::Spec

    File::Spec  was first released with perl 5.005

    $ corelist File::Spec 0.83

    File::Spec 0.83 was released with perl 5.007003

    $ corelist File::Spec 0.89

    File::Spec 0.89 was not in CORE (or so I think)

    $ corelist File::Spec::Aliens

    File::Spec::Aliens  was not in CORE (or so I think)