随机记录一条命令，查看HTTP请求响应头以及数据
tcpdump -A -s 0 ‘tcp port 80 and (((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0)’ >/tmp/tcpdump.txt
tcpdump把数据记录下来，然后去文件里搜索想要的内容，结果类似于一下：
Host: XXX
Client-ip: XXXXX
X-Forwarded-For: XXXXX
Accept: text/javascript, application/javascript, application/ecmascript, application/x-ecmascript, /; q=0.01
X-Requested-With: XMLHttpRequest
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.87 Safari/537.36
Referer: XXX
Accept-Encoding: gzip
Accept-Language: zh-CN,zh;q=0.8
Cookie: gr_user_id=XXXXX
X-Request-ID: b3b3d7d82bfa33311dd29ce44fd165c1
X-Request-HOP: 3
Trace-Pid: BC16BF2306244C18BF0BB76416FB47CB
Cdn_Sr_Ip: XXX
X-Forwarded-For: XXX