open (CQATEXTFILE, 'test.txt');

my $counter = 0;
while (<FILE>) {
  if ( ++$counter % 5 == 0 ) {
 @results=split '\t',$results;

push (@id,$results[0]);
	$_ = defined($_) ? $_ : '' for @results; # deal with empty fields
	$atom{$results[0]}=$results[1];
	$category{$results[0]}=$results[2];
	$title{$results[0]}=$results[3];

	$counter++;

  }
}