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SOME USEFUL LINUX COMMANDS

1. Tar command
=============

Create a tar archive
--------------------

root@cpanel [/home]# tar cvzf /root/avid.tar.gz avid/

avid/ is the directory name I want to archive.
avid.tar.gz is the file name that will be assigned for the archive. /root/avid.tar.gz  is the path where the tar file will be stored in to,


Extract a particular file from tar archive to a required location
--------------------------------------------------------------

root@cpanel [/home]#  tar xvzf avid.tar.gz -C /root/ avid/public_html/wp-config.php
avid/public_html/wp-config.php

In the above example the file  avid/public_html/wp-config.php from the tar file avid.tar.gz is extracted to the location /root/.


View the content inside an existing Tar archive
--------------------------------------------------


root@cpanel [/home/avid/public_html]# tar tvzf content.tar.gz
drwxr-xr-x avid/avid         0 2014-04-16 23:36 wp-content/
drwxr-xr-x avid/avid         0 2014-04-16 23:36 wp-content/plugins/
drwxr-xr-x avid/avid         0 2014-04-16 23:36 wp-content/plugins/akismet/
drwxr-xr-x avid/avid         0 2014-04-16 23:36 wp-content/plugins/akismet/views/


========================================================================

2. grep command usage


Case in-sensitive search
-------------------------
root@cpanel [/home/avid/public_html]# grep -i noBody test123.txt
 nobody
 NOBODY
 nobody
 noBODy



Search and print 3 lines after it
-------------------------------

root@cpanel [/home/avid/public_html]# grep -A 3 dummy test123.txt
 dummy
 pastha
 mytestdo
 shopcpan

Serach and print along with the 3 lines before the text
---------------------------------------------------------
root@cpanel [/home/avid/public_html]# grep -B 3 dummy test123.txt
 avid
 avid
 training
 dummy

Serach and print along with the 3 lines around the match
--------------------------------------------------------
root@cpanel [/home/avid/public_html]# grep -C 3 dummy test123.txt
 avid
 avid
 training
 dummy
 pastha
 mytestdo
 shopcpan


Search for a given string in all files recursively
-------------------------------------------------
root@cpanel [/home/avid/public_html]# grep -r dummy *
test123.txt: dummy
test321.txt: dummy


Difference using grep
---------------------------
 sdiff  test321.txt test123.txt
 hgtestdo                                                        hgtestdo
                                                              >  hgtestdo
                                                              >  HGTESTDO
                                                              >  avid
 avid                                                            avid
 training                                                        training
 dummy                                                           dummy
 pastha                                                          pastha
 mytestdo                                                        mytestdo
                                                              >  shopcpan
                                                              >  hgdomain
                                                              >  hgdomain
                                                              >  hgdomain
                                                              >  nobody
                                                              >  NOBODY
                                                              >  nobody
                                                              >  noBODy



root@cpanel [/home/avid/public_html]# grep -Fxvf test321.txt test123.txt
 HGTESTDO
 shopcpan
 hgdomain
 hgdomain
 hgdomain
 nobody
 NOBODY
 nobody
 noBODy

To get the full match using w
------------------------------------
root@cpanel [/home/avid/public_html]# grep  "body" test123.txt
 nobody
body
 nobody
root@cpanel [/home/avid/public_html]# grep -w "body" test123.txt
body
Invert the match using -v
-------------------------------
root@cpanel [/home/avid/public_html]# grep -iv "body" test123.txt
 hgtestdo
 hgtestdo
 HGTESTDO
 avid
 avid
 training
 dummy
 pastha
 mytestdo
 shopcpan
 hgdomain
 hgdomain

 hgdomain

root@cpanel [/home/avid/public_html]# grep -wv "body" test123.txt
 hgtestdo
 hgtestdo
 HGTESTDO
 avid
 avid
 training
 dummy
 pastha
 mytestdo
 shopcpan
 hgdomain
 hgdomain
 hgdomain
 nobody
NOBODY
 nobody
 noBODy







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