use IO::Handle;

use strict;
use warnings;

$| ++;

pipe(GRANDPARENT_RDR, PARENT_WTR);

if (fork()) {
	close PARENT_WTR;
	while (my $line = <GRANDPARENT_RDR>) {
		print "grand parent got $line";
	}
} else {
	close GRANDPARENT_RDR;
	pipe(PARENT_RDR, CHILD_WTR);
	if (fork()) {
		close CHILD_WTR;
		while (my $line = <PARENT_RDR>) {
			print "parent got $line";
			print PARENT_WTR $line;
		}
	} else {
		close PARENT_RDR;
		for (0..10) {
			print CHILD_WTR "$_\n";
		}
	}
}