#!/usr/bin/perl -w 
use strict; 
use IO::Socket;  
 
my ( $host, $port, $kidpid, $handle, $line );  
 
( $host, $port ) = ('localhost',9000);  
 
 
# create a tcp connection to the specified host and port 
$handle = IO::Socket::INET->new( 
    Proto    => "tcp", 
    PeerAddr => $host, 
    PeerPort => $port 
  ) 
  or die "can't connect to port $port on $host: $!"; 
print STDERR "[Connected to $host:$port]\n";  
 
# split the program into two processes, identical twins 
die "can't fork: $!" unless defined( $kidpid = fork() );  
 
# the if{} block runs only in the parent process 
if ($kidpid) {  
 
    # copy the socket to standard output 
    while ($line = <$handle>) { 
                      print STDOUT $line; 
                     } 
    kill( "TERM", $kidpid );    # send SIGTERM to child 
}  
 
# the else{} block runs only in the child process 
else {  
 
    # copy standard input to the socket 
    while ( defined( $line = <STDIN> ) ) { 
        print $handle "$line"; 
    } 
}

  
 
#!/usr/bin/perl -w 
 use IO::Socket;  
 
 
 $PORT = 9000;   # pick something not in use  
 
 $server = IO::Socket::INET->new( Proto     => 'tcp', 
                                  LocalPort => $PORT, 
                                  Listen    => SOMAXCONN, 
                                  Reuse     => 1); 
 die "can't setup server" unless $server;  
 
 while ($client = $server->accept()) { 
   while ( <$client>) { 
       print "$_"; 
       print $client "$_"; 
   }  
 }

#!/usr/bin/perl 
 
use strict; 
use warnings; 
use IO::Socket; 
use constant ECHO_PORT => 9000; 
 
my ($bytes_out, $bytes_in, $quit) = (0,0,0); 
 
$SIG{INT} = sub { $quit++ }; 
 
my $port = shift || ECHO_PORT; 
 
my $sock = IO::Socket::INET->new(Listen    => 20, 
                                 LocalPort => $port, 
                                 Timeout   => 60, 
                                 Reuse     => 1, 
) or die "Can't create listening socket: $!\n"; 
 
warn "waiting for connections on port $port...\n"; 
 
while ( !$quit ) { 
    next unless my $session = $sock->accept; 
 
    my $peer = gethostbyaddr($session->peeraddr, AF_INET) || $session->peerhost; 
    my $port = $session->peerport; 
 
    warn "Connection from [$peer, $port]\n"; 
 
    while ( <$session> ) { 
        $bytes_in += length($_); 
        $bytes_out += length($_); 
        print "client $peer sent '$_'"; 
        print $session $_; 
        $quit++ if $bytes_in eq 'q'; 
    } 
    warn "Connection from [$peer, $port] finished\n"; 
    close $session; 
} 
warn "bytes_received = $bytes_in, bytes_sent = $bytes_out\n"; 
close $sock or warn $@;

#!/usr/bin/perl 
 
use strict; 
use warnings; 
use IO::Socket; 
 
my ($bytes_out, $bytes_in) = (0,0); 
my $host = shift || 'localhost'; 
my $port = shift || 9000; 
 
my $socket = IO::Socket::INET->new( Proto    => 'tcp', 
                                    PeerAddr => $host, 
                                    PeerPort => $port, 
) or die "can't connect to port $port on $host: $!"; 
 
$socket->autoflush(1); 
 
while ( my $msg_out = STDIN->getline ) { 
    last if $msg_out =~ /^q/i; 
    print $socket $msg_out; 
 
    my $msg_in = <$socket>; 
    print $msg_in; 
 
    $bytes_out += length($msg_out); 
    $bytes_in  += length($msg_in); 
} 
 
$socket->close or warn $@; 
print "bytes_sent = $bytes_out, bytes_received = $bytes_in\n";

#!/usr/bin/perl 
 
print "Hello World!\n\n";