#!/usr/bin/perl -w
#Traditional IO::Select Example 
use IO::Select;
use IO::Socket;

$Server = new IO::Socket::INET(Listen => 0, LocalPort => 4000, Reuse => 0) || die('Can not open port 4000');
$Select = new IO::Select( $Server );

while(@allSockets = $Select->can_read) {
  foreach $ClientSocket (@allSockets) {
    if($ClientSocket == $Server) {            
      $newClient = $Server->accept;      
      $Select->add($newClient);      
    } else {
        ....
    }
}