use IO::Socket::INET;

$socket = IO::Socket::INET->new(
    PeerAddr => '127.0.0.1',
    PeerPort => 5555,
    Proto    => 'tcp',
    Type     => SOCK_STREAM,
    Timeout => 5,
) or die $@;

$socket->autoflush(1);

print $socket "Hello!\n";

my $line = "";
sysread($socket, $line, 1024);

print "ANSWER: " . $line;

close($socket);