true|false string()=ASCII字符列表 path()=string()表示文件或目录路径 ip_address()={N1,N2,N3,N4}%IPv4|{K1,K2,K3,K4,K5,K6
hostname()|ipaddress() hostname()= string()-DNShostname ip_address()= {N1,N2,N3,N4}%IPv4|{K1,K2,K3,K4,K5,K6