Is the format of the file 100% reliable? That is, if skipping even-numbered lines works today (or one *one* server), will it necessarily work tomorrow (or on *another* server)?

If so, then I'll second dmmiller2k's answer.

If not, then you might want to consider using a regex to match the lines you want to omit. It will probably take more time than testing $., so you might want to use Benchmark, if that's a concern for your application. Assuming you want to omit the referer line that lists your own URL, you could do something like this:

open (DB, "<$data_file");                    
while (<DB>)                                        
  {
   next if m!www.yourserver.com/your/referer/here!;
   $row = $_;                               
   chop $row;                                 
   @fields = split (/\|/, $row);
   print "$fields[0]";
  }
close (DB);
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