/// <summary>
        /// 登陆后命令
        /// </summary>
        /// <param name="cmd"></param>
        static void excutecmd(string cmd)
        {
            string[] cmds = cmd.Split(' ');
            cmd = cmds[0];
            switch (cmd)
            {
            //登出
            case "logout":
                CMD.Login.logout(ref user);
                break;

            //清屏
            case "clr":
                Console.Clear();
                break;

            //取消该用户
            case "cancleuser":
                UserOperation.cancle(user);
                Login.logout(ref user);
                break;

            //更改密码
            case "modifypsw":
                PWDChanger.change(user);
                break;

            //输出当前目录下所有文件及子目录
            case "dir":
                Dir.GetDir(user);
                break;

            //显示当前目录名
            case "cd":
                Console.WriteLine(user.GetSinglePath());
                break;

            //进入下一级目录
            case "cdfore":
                PathChanger.fore(user, cmds[1]);
                break;

            //返回上一级目录
            case "cdback":
                PathChanger.back(user);
                break;

            //返回根目录
            case "cdroot":
                PathChanger.root(user);
                break;

            //新建文件夹
            case "mkdir":
                DirectoryOperation.makedir(user, cmds[1]);
                break;

            //删除目录
            case "my_deletedir":
                DirectoryOperation.deletedir(user, cmds[1]);
                break;

            //新建一个文件
            case "my_create":
                FileOperation.create(user, cmds[1]);
                break;

            //删除一个文件
            case "my_deletefile":
                FileOperation.delete(user, cmds[1]);
                break;

            //输入错误
            default:
                if (cmd.Trim() == "\n")
                {
                    Console.WriteLine();
                }
                else
                {
                    Console.WriteLine("没有这样的命令,请检查");
                }
                break;
            }
        }