A better command than man, help the software.

Source: Internet
Author: User

Lab Environment:

VMware Workstation 11

Under the centos6.7 system

ip: Firewall off Setenforce 0

Putty (SSH remote connection software)

Software Introduction:

What is cheat?

Cheat is an interactive cheat sheet application that is distributed to Linux command line users under the GNU General Public License. It provides a display of Linux command use cases, including all of the options and short but understandable features of the command.

Experimental process:

' Cheat ' has two main dependencies-' Python ' and ' pip ', before installing ' Cheat ', make sure your system has Python and Pip installed.

First, install Pip

[email protected] ~]# Yum install python-pip-y

Second, installation cheat

[[email protected] ~]# pip install  cheatcollecting cheat/usr/lib/python2.6 /site-packages/pip/_vendor/requests/packages/urllib3/util/ssl_.py:90: insecureplatformwarning: a  true sslcontext object is not available. this prevents urllib3  from configuring ssl appropriately and may cause certain ssl  connections to fail. for more information, see https:// Urllib3.readthedocs.org/en/latest/security.html#insecureplatformwarning.  insecureplatformwarning   Downloading cheat-2.1.25.tar.gz  (43kB)     100% | ████████████████████████████████| 45kb 111kb/scollecting docopt>=0.6.1  (from cheat )   Downloading docopt-0.6.2.tar.gzCollecting pygments>=1.6.0  (From cheat)   downloading pygments-2.1.3-py2.py3-none-any.whl  (755kB)     100% |████████████████████████████████| 757kB  172kb/sinstalling collected packages: docopt, pygments, cheat  running  setup.py install for docopt  Running setup.py install for  cheatsuccessfully installed cheat-2.1.25 docopt-0.6.2 pygments-2.1.3

Third, how to use the software

[[email protected] ~]# cheat tcpdump# tcpdump is a packet  analyzer. it allows the user to intercept and display tcp/ip#  and other packets being transmitted or received over a  network.  (Cf wikipedia). # note: => google.com# intercepts  all packets on eth0tcpdump -i eth0# Intercepts all packets  from/to host intercepts all packets  on all interfaces from / to port 80# -nn = > Disables name resolution for IP addresses and port  Numbers.tcpdump -nn -i any host and port 80# make  a grep on tcpdump  (ASCII) # -a  => show only ascii in packets.# -s0 = > by default, tcpdump only captures 68 bytes.tcpdump -i -a  any host and port 80 | grep  ' User-agent ' #  with ngrep# -d eth0 => to force eth0  (else ngrep work  on all interfaces) # -s0 => force ngrep to look at  the entire packet.  (default snaplen: 65536 bytes) ngrep  ' User-Agent '   Host and port 80# intercepts all packets on all  interfaces from / to or on port  80tcpdump  ' host  ( or )  and port 80 '  - i any# intercepts all packets syn and fin of each tcp session.tcpdump  ' tcp[ tcpflags] &  (Tcp-syn|tcp-fin)  != 0 ' # to display syn and fin  packets of each tcp session to a host that is not  on our networktcpdump  ' tcp[tcpflags] &  (tcp-syn|tcp-fin)  != 0  and not src and dst net local_addr ' # to display all  ipv4 http packets that come or arrive on port 80 and  that contain only data  (no syn, fin no, no packet containing  an ack) tcpdump  ' tcp port 80 and  (((ip[2:2] -  (IP[0]&0XF) <<2)  -  ((tcp[12]&0xf0) >>2))  != 0) ' # saving captured  Datatcpdump -w file.cap# rEading from capture filetcpdump -r file.cap# show content in hexa # change -x to -xx => show extra header  (Ethernet). tcpdump  -x# show content in hexa and ascii# change -x to -xx  => show extra header  (Ethernet). Tcpdump -x# note on packet  maching:# port matching:# - portrange 22-23# - not port 22#  - port ssh# - dst port 22# - src port 22## host  matching:# - dst host - not dst host  - src net mask - src net

You can see that the output is easy to understand and use clearly.

Reference article link: http://os.51cto.com/art/201409/450709.htm

This article from "A few" blog, declined reprint!

A better command than man, help the software.

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