详解Linux系统中字符串搜索命令ngrep的用法

ngrep 是grep的网络版，他力求更多的grep特征，用于搜寻指定的数据包。由于安装ngrep需用到ibpcap库， 所以支持大量的操作系统和网络协议，能识别tcp、udp和icmp包。

安装ngrep
下载地址

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代码如下:

git clone git://git.code.sf.net/p/ngrep/code ngrep-code

进入目录

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代码如下:

cd ngrep-code
./configure --with-pcap-includes=/usr/local/include/pcap
make
make install

选项

-h     is help/usage
-v    is version information
-q    is be quiet (don't print packet reception hash marks)静默模式，如果没有此开关，未匹配的数据包都以“#”显示
-e    is show empty packets 显示空数据包
-i     is ignore case 忽略大小写
-v    is invert match 反转匹配
-r   is don't do privilege revocation logic
-x    is print in alternate hexdump format 以16进制格式显示
-x   is interpret match expression as hexadecimal 以16进制格式匹配
-w   is word-regex (expression must match as a word) 整字匹配
-p   is don't go into promiscuous mode 不使用混杂模式
-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在每个匹配的包之前显示时间戳
-t    is print delta timestamp every time a packet is matched显示上一个匹配的数据包之间的时间间隔
-m   is don't do multi-line match (do single-line match instead)仅进行单行匹配
-i     is read packet stream from pcap format file pcap_dump 从文件中读取数据进行匹配
-o   is dump matched packets in pcap format to pcap_dump 将匹配的数据保存到文件
-n    is look at only num packets 仅捕获指定数目的数据包进行查看
-a   is dump num packets after a match匹配到数据包后dump随后的指定数目的数据包
-s    is set the bpf caplen
-s   is set the limitlen on matched packets
-w  is set the dump format (normal, byline, single, none) 设置显示格式byline将解析包中的换行符
-c    is force the column width to the specified size 强制显示列的宽度
-p   is set the non-printable display char to what is specified
-f   is read the bpf filter from the specified file 使用文件中定义的bpf(berkeley packet filter)
-n   is show sub protocol number 显示由iana定义的子协议号
-d   is use specified device (index) instead of the pcap default

应用举例：

捕获所有post请求(加个-w byline 参数后,将解析包中的换行符)：

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代码如下:

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.
.
<?xml version="1.0" encoding="utf-8"?><soap:envelope xmlns:xsi="http://www.w3.org/2001/xmlschema-instance" xmlns:xsd="http://www.w3.org/2001/xmlschema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"> <soap:body> <request xmlns="http://ctrip.com/"> <requestxml>&lt;request&gt;
&lt;header allianceid="***" sid="***" timestamp="1393554304685" requesttype="ota_hotelsearch" signature="b166cdf5422a6da5ba81a08036e938e7"/&gt;
&lt;hotelrequest&gt;
&lt;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"&gt;
&lt;ns:ota_hotelsearchrq version="1.0" primarylangid="zh"
xsi:schemalocation="http://www.opentravel.org/ota/2003/05 ota_hotelsearchrq.xsd"