`cleanup`

      next unless /\t*chain\s+"chain([0-9])"/;
      $chain_number = $1;
      $chain[$chain_number] = cleanup($_);
      &printout if $chain_number == 7;

Now we have Variable use immediately follows assignment

      next unless /\t*chain\s+"chain([0-9])"/;
      $chain[$1] = cleanup($_);
      &printout if $1 == 7;