使用 tcpdump 时，如何仅打印数据包数据？
例如（匿名）：
sudo tcpdump -X 'tcp port 80 and (((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0)'
10:23:59.521551 IP dhcp227.asdfasdf.com.47142 > sjc-not7.sjc.dropbox.com.www: Flags [P.], seq 5074:5341, ack 6420, win 2448, options [nop,nop,TS val 7955335 ecr 585615613], length 267
0x0000: 4500 013f 7913 4000 4006 72ee ac10 01e3 E..?y.@.@.r.....
0x0010: c732 d894 b826 0050 9455 3f65 51f9 a5f4 ./...&.P.U?eQ...
0x0020: 8018 0990 4ee9 0000 0101 080a 0079 6387 ....N........yc.
0x0030: 22e7 c8fd 4745 5420 2f73 7562 7363 7269 "...GET./subscri
0x0040: …