note monsoon <p>You mean something like this?</p> <code> while(<>){ chomp; if(/(ID=.+)$/){ if(++$ids{$1} > 1){ say $_, $ids{$1}; next; } } say; } </code> <p>Try and get yourself a copy of the Perl Cookbook. It usually comes handy for such tasks.</p> 977715 977715