use strict; use warnings; my $name = ''; my %id_list; open (STDIN,"perl first_program.pl|") || die "$!"; open (OUT, ">", "out.txt") || die "$!"; while( my $line_in = ) { line_in =~ m/^([^\t]*)(?:[^\|]*\|){3}([^\|]*)/; unless($name eq $1) { %id_list = (); $name = $1; } next if $id_list{$2}++; print OUT "$line_in"; } #### use strict; use warnings; use Benchmark; my $line_in = "mmenr\thh|gg|kk|3445|uu|zzz\t234\twwe\twe\tqw\t233\n"; Benchmark::cmpthese( 1000000, { 'split' => sub { chomp($line_in); my @line_array = split(/\t/,$line_in); my @subline_array = split(/\|/, $line_array[1]); }, 're' => sub { my ($name, $id) = ($line_in =~ m/^([^\t]*)(?:[^\|]*\|){3}([^\|]*)/); } }); __END__ Rate split re split 84962/s -- -68% re 266667/s 214% --