readdir isn't for people, its for computers, don't use readdir, use Path::Tiny, you'll like it, I promise, see Re: Text merge concept in perl (Path::Tiny

selective_delete( $destinationDir , \@KEEP );



sub selective_delete {
    my( $thedir, $keepers ) = @_;
    my %keepers = map { path( $thedir , $_ ) => 1; } @$keepers;
    my @goners = grep { not exists $keepers{$_} } path( $thedir )->chi
+ldren;
    for my $goner ( @goners ){
        path( $goner )->remove;
    }
    return;
}
[download]

https://metacpan.org/pod/Path::Tiny#children