use strict;
use warnings;

use IO::Socket ();

my $peer_port = shift(@ARGV)
or die("Specify the port on the command line.$/");

my $server_fh = IO::Socket->new(
    Domain   => IO::Socket::AF_INET(),
    Proto    => 'tcp',
    PeerAddr => '127.0.0.1',
    PeerPort => $peer_port,
) or die("Unable to connect to server: $!$/");

print('Connected to ', $server_fh->peerhost(), ':', $server_fh->peerport(), '.', $/);

print('Type stuff to be uppercased by server. Blank line to exit.', $/);

for (;;) {
   last if (!defined($_ = <STDIN>) || $_ eq $/);
   print $server_fh $_;
   last if (!defined($_ = <$server_fh>));
   print;
}

print('Connection closed by server or by error or by request.', $/);