#!/usr/bin/perl
use strict;
use warnings;
use 5.010;

require LWP::UserAgent;
foreach my $url ('http://www.google.de','https://www.youtube.com/') {
    my $pid;
    # Vater
    if ($pid = fork()) {
        say 'wie kann man hier feststellen, ob beide Soehne fertig sind?';
    }
    # Sohn
    else {
        my $ua = LWP::UserAgent->new;
        my $response = $ua->get($url);
        if ($response->is_success) {
            say $url.' liefert '.length($response->decoded_content).' Byte';
        }
        else {
            die 'Fehler '.$response->status_line.' in '.__LINE__;
        }
    }
}