sub sort_aoa {
  my( $array, $column ) = @_;
  return sort { $a->[$column] cmp $b->[$column] } @$array;
}

##</code><code>##

sub sort_lines_by_column {
  my( $array, $column ) = @_;
  return sort {
    return( (split ' ', $a)[$column] cmp (split ' ', $b)[$column] );
  } @$array;
}