在networking方面，最基礎(chǔ)的是BSD socket編程，但往往perl入門時在這個方面，最頭疼的無疑是如何開始，如何Step by step。最好的藥方就是Example，一段完整的可以運行（working）的代碼，通過實踐來感受遠(yuǎn)比看枯燥的manual來得深刻。

     以下給出幾段使用Socket及IO::Socket編寫的Server/client，他們能實現(xiàn)最簡單但是卻最基本的任務(wù)，包括一個forking/accept的模型。可以直接復(fù)制這些代碼，然后小加修改即可開發(fā)一些小型的tcp/udp應(yīng)用了。

TCP 客戶端, Socket 模塊

簡介：實現(xiàn)從服務(wù)器端讀取一行信息然后返回
代碼如下:
#!/usr/bin/perl -w
# tcp_socket_cli.pl
use strict;
use Socket;
my $addr = $ARGV[0] || '127.0.0.1';
my $port = $ARGV[1] || '3000';
my $dest = sockaddr_in($port, inet_aton($addr));
my $buf = undef;
socket(SOCK,PF_INET,SOCK_STREAM,6) or die "Can't create socket: $!";
connect(SOCK,$dest)                or die "Can't connect: $!";
my $bs = sysread(SOCK, $buf, 2048); # try to read 2048
print "Received $bs bytes, content $buf/n"; # actually get $bs bytes
close SOCK;

執(zhí)行結(jié)果：
perl tcp_socket_cli.pl localhost 25
Received 41 bytes, content 220 ESMTP Postfix - ExtMail 0.12-hzqbbc

TCP 服務(wù)端 Socket模塊, forking/accept模型
簡介：一個多進(jìn)程的TCP服務(wù)器，sample中實現(xiàn)了daytime的功能
代碼如下:
#!/usr/bin/perl -w
# tcp_socket_dt_srv.pl
use strict;
use Socket;
use IO::Handle;
use POSIX qw(WNOHANG);
my $port     = $ARGV[0] || '3000';
my $proto    = getprotobyname('tcp');
$SIG{'CHLD'} = sub {
     while((my $pid = waitpid(-1, WNOHANG)) >0) {
          print "Reaped child $pid/n";
      }
};
socket(SOCK, AF_INET, SOCK_STREAM, getprotobyname('tcp'))
    or die "socket() failed: $!";
setsockopt(SOCK,SOL_SOCKET,SO_REUSEADDR,1)
    or die "Can't set SO_REUSADDR: $!" ;
my $my_addr = sockaddr_in($port,INADDR_ANY);
bind(SOCK,$my_addr)    or die "bind() failed: $!";
listen(SOCK,SOMAXCONN) or die "listen() failed: $!";
warn "Starting server on port $port.../n";
while (1) {
     next unless my $remote_addr = accept(SESSION,SOCK);
     defined(my $pid=fork) or die "Can't fork: $!/n";

     if($pid==0) {
          my ($port,$hisaddr) = sockaddr_in($remote_addr);
          warn "Connection from [",inet_ntoa($hisaddr),",$port]/n";
          SESSION->autoflush(1);
          print SESSION (my $s = localtime);