for my $i (2..12)
{
  for my $k (5..18)
  {
     open my $handle, "<", "path" or die; # my means that the $handle here is a new one on each call.
     ...
     # closed is called automatically here
  }
}
##</code><code>##

    my @columns = split(/\s+/, $line);    # split columns on whitespace

    my $col1 = shift @columns;  # column 1 (throw away)
    my $col2 = shift @columns;  # column 2 (throw away)
    my $col3 = shift @columns;  # column 3 (special - keep this one)
    my $result = sprintf("%8.3f", $col3); # special format for col 3