Select Code to Download

for my $nr (1..2) {
 for my $line (read_file('file'.$nr)) {
...
  push @{$data[$nr - 1]->{shift(@cols)}},\@cols;
 }
}

# expecting file3 line in @col
my @results = ($col[0],$col[3]);
...
   $diff_a <=> $diff_b;
  } @{$dataset->{$col[0]}})[0]->[2];
}