my $pid = open IN, '-|',
    qq[ perl -E"say scalar localtime, sleep 1 for 1.. $ARGV[0]" ]
    or die $!;

my $buf = '';
if (!do {
    local $SIG{ ALRM } = sub {
        kill -9, $pid;
    };
    alarm 5;
    $buf .= $_ while <IN>;
    waitpid($pid, 0);
    alarm 0;
    die("Can't waitpid: $!\n")                      if $? == -1;
    die("Child killed by signal ".($? & 0x7F)."\n") if $? & 0x7F;
    die("Child returned error ".($? >> 8)."\n")     if $? >> 8;
    1
}) {
    waitpid($pid, 0);
    die("Timeout\n");
}