while(1){
        print "Hello\n";
        sleep(2);
}

##</code><code>##

my @lines;
while(1){
        sleep(10);
        if (<STDIN>){#Non-blocking reading
                print "Reading lines...";
                @lines=<STDIN>;
                print "@lines";
        }else{
                print "No lines received.\n";
        }
}

##</code><code>##

$./producer.pl
Hello
Hello

$echo "Hello" | ./consumer.pl
Hello