sub unzip {
    my ($archive, $want, $dir) = shift;
    my $zip = Archive::Zip->new($dir.$archive);
    foreach my $file ($zip->members) {
        next unless ($file->fileName eq $want);
        $file->extractToFileNamed($dir.$want);
    }   
    croak "There was a problem extracting $want from $archive" unless (-e $dir.$want);
    return 1;
}