filter_five_end.pl

#!/usr/bin/perl
use strict;
use warnings;

my $prev_id = "";
my @five;
my @three;
my @unmap;
my @mid;
my @all;
my $counter = 0;


while (<STDIN>){
	chomp;
	if (/^@/){
		print $_."\n";
		next;
	}
	my ($id, $flag, $chr_from, $loc_from, $mapq, $cigar, $d1, $d2, $d3, $read, $read_qual, @rest) = split /\t/;
	my $bin = reverse(dec2bin($flag));
	my @binary = split(//,$bin);
	if ($prev_id ne $id && $prev_id ne ""){
		if ($counter == 1){
			if (@five == 1){
				print $five[0]."\n";
			}
			else{
				my ($id_1, $flag_1, $chr_from_1, $loc_from_1, $mapq_1, $cigar_1, $d1_1, $d2_1, $d3_1, $read_1, $read_qual_1, @rest_1) = split /\t/, $all[0];
				my $bin_1 = reverse(dec2bin($flag_1));
				my @binary_1 = split(//,$bin_1);
				$binary_1[2] = 1;
				my $bin_1_new = reverse(join("",@binary_1));
				my $flag_1_new =  bin2dec($bin_1_new);
				print(join("\t",$id_1, $flag_1_new, $chr_from_1, $loc_from_1, $mapq_1, $cigar_1, $d1_1, $d2_1, $d3_1, $read_1, $read_qual_1, @rest_1)."\n");
			}
		}
		elsif ($counter == 2 && @five == 1){
			print $five[0]."\n";
		}
		else{
			my ($id_1, $flag_1, $chr_from_1, $loc_from_1, $mapq_1, $cigar_1, $d1_1, $d2_1, $d3_1, $read_1, $read_qual_1, @rest_1) = split /\t/, $all[0];
			my $bin_1 = reverse(dec2bin($flag_1));
			my @binary_1 = split(//,$bin_1);
			$binary_1[2] = 1;
			my $bin_1_new = reverse(join("",@binary_1));
			my $flag_1_new =  bin2dec($bin_1_new);
			print(join("\t",$id_1, $flag_1_new, $chr_from_1, $loc_from_1, $mapq_1, $cigar_1, $d1_1, $d2_1, $d3_1, $read_1, $read_qual_1, @rest_1)."\n");
		}

		$counter = 0;
		undef @unmap;
		undef @five;
		undef @three;
		undef @mid;
		undef @all;
	}

	$counter++;
	$prev_id = $id;
	push @all,$_;
	if ($binary[2]==1){
		push @unmap,$_;
	}
	elsif ($binary[4]==0 && $cigar =~ m/^[0-9]*M/ || $binary[4]==1 && $cigar =~ m/.*M$/){
		push @five, $_;
	}
	elsif ($binary[4]==1 && $cigar =~ m/^[0-9]*M/ || $binary[4]==0 && $cigar =~ m/.*M$/){
		push @three, $_;
	}