Linux commands and utilities

1. tar command examples

·         Create a new tar archive.

         $ tar cvf archive_name.tar dirname/

·         Extract from an existing tar archive.

         $ tar xvf archive_name.tar

·         View an existing tar archive.

         $ tar tvf archive_name.tar

2. grep command examples

·         Search for a given string in a file (case in-sensitive search). 

$ grep -i "the" demo_file

·         Print the matched line, along with the 3 lines after it.

         $ grep -A 3 -i "example" demo_text

·         Search for a given string in all files recursively

         $ grep -r "DBA" *

3. find command examples

·         Find files using file-name ( case in-sensitve find)

         # find -iname "DBA"

·         Execute commands on files found by the find command

         $ find -iname "DBA" -exec md5sum {} \;

·         Find all empty files in home directory

         # find ~ -empty

4. ssh command examples

·         Login to remote host

         ssh -l oracle remotehost.example.com

·         Debug ssh client

         ssh -v -l oracle remotehost.example.com

·         Display ssh client version

         $ ssh -V

5. awk command examples

·         Remove duplicate lines using awk

         $ awk '!($0 in array) { array[$0]; print }' temp

·         Print all lines from /etc/passwd that has the same uid and gid

         $awk -F ':' '$3==$4' passwd.txt

·         Print only specific field from a file.

         $ awk '{print $2,$5;}' employee.txt

6. Vim command examples

·         Go to the 143rd line of file

         $ vim +143 filename.txt

·         Go to the first match of the specified

         $ vim +/search-term filename.txt

·         Open the file in read only mode.

         $ vim -R /etc/passwd

7. diff command examples

·         Ignore white space while comparing.

# diff -w name_list.txt name_list_new.txt

 2c2,3

< John Doe --- > John M Doe

8. Unzip command examples

·         To extract a *.zip compressed file:

         $ unzip test.zip

·         View the contents of *.zip file (Without unzipping it):

$ unzip -l jasper.zip

Archive:  jasper.zip

Length     Date   Time    Name

--------    ----   ----    ----

40995  11-30-98 23:50   META-INF/MANIFEST.MF

32169  08-25-98 21:07   classes_

15964  08-25-98 21:07   classes_names

10542  08-25-98 21:07   classes_ncomp

9. free command examples

·         If you want to quickly check how many GB of RAM your system

If you want to see a total memory (including the swap)

 

10. yum command examples

·         To install apache using yum.

         $ yum install httpd

·         To upgrade apache using yum.

         $ yum update httpd

·         To uninstall/remove apache using yum.

         $ yum remove httpd

11. yum command examples

uuencode filename filename |mailx -s subject mail_id 

12. To list who is logged in, load average and their processes

13. To use multiple shell windows from a single SSH session

screen -s rman -> to save the screen in Linux box

screen -x rman -> to open saved session

14. How to extract multi-part, e.g. .z01, .z02 type of zip files on Linux

In order to extract on Ubuntu, do the following:

    zip -s- dac_win_11g_infa_linux_64bit_951.zip -O output.zip

This will gather the Input.zip file and all following .z0x in one file called output.zip, which you can then extract and do whatever you want on it,

e.g.

                        zip -s- dac_win_11g_infa_win_64bit_901.zip -O output.zip

15. To deinstall and install jdk

    [root@ogslab2 java]# rpm -qa jdk

    jdk-1.6.0_43-fcs.i586

   [root@ogslab2 java]# rpm -ev jdk-1.6.0_43-fcs.i586

   [root@ogslab2 ogsbkp]# rpm -ivh jdk-6u24-linux-i586.rpm

Preparing...                ########################################### [100%]

1:jdk                       ######################################## [100%]

    Unpacking JAR files...

              rt.jar...

              jsse.jar...

             charsets.jar...

               tools.jar...

               localedata.jar...

               plugin.jar...

                javaws.jar...

                deploy.jar.

 

16. Create download-file-list.txt in you user home (here its mine  

     mxm129)

[mxm129@bdopprka001  SPSR15151]$ pwd

/export/home/mxm129/SPSR15151

[mxm129@bdopprka001  SPSR15151]$ ls -ltr download-file-list.txt

-rwxrwxrwx 1 mxm129 efx 2156 Dec 26 00:23 download-file-list.txt

[mxm129@bdopprka001  SPSR15151]$ cat download-file-list.txt

http://scm.devcentral.equifax.com/svn/GCP/Oracle%20Financials/branches/DEV%20(Developer%20Only)/Oracle%20R12%20CORP/XXAR/ldt/XXAR_BCP_AUTOMATION_CP.ldt

http://scm.devcentral.equifax.com/svn/GCP/Oracle%20Financials/branches/DEV%20(Developer%20Only)/Oracle%20R12%20CORP/XXAR/ldt/XXAR_BCP_AUTO_OUT_CP.ldt

[mxm129@bdopprka001  SPSR15151]$

wget --user=mxm129 --password=********* -i download-file-list.txt

When you run above commnad it will download all latest version of files from SVN. Give fill permission to all below files ....

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

[mxm129@bdopprka001  SPSR15151]$ ls -ltr

total 480

-rwxrwxrwx 1 mxm129 efx 20514 Dec  1 13:48 XXAR_BCP_AUTO_OUT_CP.ldt

-rwxrwxrwx 1 mxm129 efx 23463 Dec  1 13:48 XXAR_BCP_AUTOMATION_CP.ldt

-rwxrwxrwx 1 mxm129 efx  2156 Dec 26 00:23 download-file-list.txt

[mxm129@bdopprka001  SPSR15151]$

        

        Copy all files from (/export/home/mxm129/SPSR15151) to       

       /export/home/appllut/SPSR15151 using apps user

17. To get more info about the listening ports in linux machine
          Login to root user and execute below cmds,

              fuser 8453/tcp
              8453/tcp:             3813
              lrwxrwxrwx 1 vivek vivek 0 2010-10-29 11:00 /proc/3813/exe -> /usr/bin/transmission

                  [OR]

              lsof -i TCP:8453
              lrwxrwxrwx 1 vivek vivek 0 2010-10-29 11:00 /proc/3813/exe -> /usr/bin/transmission