ngrep 是grep的網絡版，他力求更多的grep特征，用於搜尋指定的數據包。由於安裝ngrep需用到ibpcap庫， 所以支持大量的操作系統和網絡協議，能識別TCP、UDP和ICMP包。
安裝ngrep
下載地址
代碼如下:
git clone git://git.code.sf.net/p/ngrep/code ngrep-code
進入目錄
代碼如下:
cd ngrep-code
./configure --with-pcap-includes=/usr/local/include/pcap
make
make install
選項
-h is help/usage
-V is version information
-q is be quiet (don't print packet reception hash marks)靜默模式，如果沒有此開關，未匹配的數據包都以“#”顯示
-e is show empty packets 顯示空數據包
-i is ignore case 忽略大小寫
-v is invert match 反轉匹配
-R is don't do privilege revocation logic
-x is print in alternate hexdump format 以16進制格式顯示
-X is interpret match expression as hexadecimal 以16進制格式匹配
-w is word-regex (expression must match as a word) 整字匹配
-p is don't go into promiscuous mode 不使用混雜模式
-l is make stdout line buffered
-D is replay pcap_dumps with their recorded time intervals
-t is print timestamp every time a packet is matched在每個匹配的包之前顯示時間戳
-T is print delta timestamp every time a packet is matched顯示上一個匹配的數據包之間的時間間隔
-M is don't do multi-line match (do single-line match instead)僅進行單行匹配
-I is read packet stream from pcap format file pcap_dump 從文件中讀取數據進行匹配
-O is dump matched packets in pcap format to pcap_dump 將匹配的數據保存到文件
-n is look at only num packets 僅捕獲指定數目的數據包進行查看
-A is dump num packets after a match匹配到數據包後Dump隨後的指定數目的數據包
-s is set the bpf caplen
-S is set the limitlen on matched packets
-W is set the dump format (normal, byline, single, none) 設置顯示格式byline將解析包中的換行符
-c is force the column width to the specified size 強制顯示列的寬度
-P is set the non-printable display char to what is specified
-F is read the bpf filter from the specified file 使用文件中定義的bpf(Berkeley Packet Filter)
-N is show sub protocol number 顯示由IANA定義的子協議號
-d is use specified device (index) instead of the pcap default
應用舉例：
捕獲所有post請求(加個-W byline 參數後,將解析包中的換行符)：
代碼如下:
ranger@ranger:~$ sudo ngrep -q -W byline "(POST).*"
interface: eth0 (192.168.122.0/255.255.254.0)
match: (POST).*
T 192.168.122.74:46048 -> 140.207.228.58:80 [A]
POST /Hotel/OTA_HotelSearch.asmx?wsdl HTTP/1.1.
Content-Type: text/xml; charset=UTF-8.
SOAPAction: http://ctrip.com/Request.
Accept-Encoding: gzip, deflate.
Content-Length: 1330.
Accept: */*.
Accept-Language: zh-cn.
User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0).
UA-CPU: x86.
Accept-Encoding: gzip, deflate.
Connection: close.
Host: openapi.ctrip.com.
.
<Header AllianceID="***" SID="***" TimeStamp="1393554304685" RequestType="OTA_HotelSearch" Signature="B166CDF5422A6DA5BA81A08036E938E7"/>
<HotelRequest>
<RequestBody xmlns:ns="http://www.opentravel.org/OTA/2003/05" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<ns:OTA_HotelSearchRQ Version="1.0" PrimaryLangID="zh"
xsi:schemaLocation="http://www.opentravel.org/OTA/2003/05 OTA_HotelSearchRQ.xsd"