$ md tmpblah

$ echo > tmpblah\aone.pl

$ echo > tmpblah\bOne.pl

$ echo > tmpblah\cONe.pl

$ echo > tmpblah\dONE.pl

$ perl -MPath::Class::Rule -le "print for Path::Class::Rule->new->file->iname(qr/.one.pl/)->all(q/tmpblah/) "
tmpblah\aone.pl
tmpblah\bOne.pl
tmpblah\cONe.pl
tmpblah\dONE.pl