my $line = '';
	while (<$in>) {
		$line .= $_;
		next if m/\\$/;
		chomp $line;
		my @cols = ('');
		my @tabs = split /\t/, $line;
		foreach (@tabs) {
			$cols[$#cols] =~ m/\\$/ and do {
				$cols[$#cols] .= "\t$_";
				next;
			};
			push @cols, $_;
		}
		shift @cols;
                <processing done here>
		$line = '';
	}