客户端的开发小程序。linux中各shell命令的运用，使用消息队列和通信进程-The development of client applets. linux in order to use the shell, use the message queue and communication process

io多路复用用于一个服务器端接收多个客户端请求，实现非阻塞数据传输(IO multiplexing is used to receive multiple client requests at one server to achieve non blocking data transmission)