Linux Commands | Oracle Identity And Access Management Help Guide

1)What does '~' represent in linux commands ?

Ans : '~' is a shortcut for the home directory.

 So cd ~/mydirectory will move to mydirectory if there is such a directory in your home folder,     otherwise it will throw a directory does not exist error.

2)How to transfer files from Windows local machine to Remote Linux machine ?

Ans : Use WinSCP software. Select the file from local machine and upload it to the remote machine.

3)What is the Linux command to check whether a file is installed or not ?

Ans : rpm –q filename

4)What is the Linux command to confirm the deletion before deleting a file?

Ans : rm -i filename(s)

5)What is the Linux command to Extract a ZIP file to a different directory?

Ans : If you want to put the contents of the ZIP file in a different directory than the current one, use the -d switch.

For example, to decompress the Trash.zip file to /home/music/Nitheesh/Trash, you'd use the following syntax:

unzip Trash.zip -d "/home/music/Nitheesh/Trash"

6)How to set the default java version in Linux system? OR Many java versions are available in a Linux system, how to set one among it as the default java version?

Ans : Check available Java versions on your Linux system by using update-alternatives command,

 $ sudo update-alternatives --display java

Now that there are suitable candidates to change to, you can switch the default Java version among available Java JREs by running the following command,

 $ sudo update-alternatives --config java

When prompted, select the Java version you would like to use,1 or 2 or 3 or etc..

Now you can verify the default Java version changed as follows.

 $ java -version

7)How to change the port that weblogic listens to?

Ans : We can use the Web Logic Scripting Tool to change the listening port,
Start WLST by running,
/home/nitheesh/Oracle/Middleware/wlserver_10.3/common/bin/wlst.sh
Follow the below commands to change the listening port(in this case to 7778),

wls:/offline> readDomain ('/home/nitheesh/Oracle/Middleware/user_projects/domains/base_domain')
wls:/offline/base_domain> cd ('Server')
wls:/offline/base_domain/Server> ls ()
drw- AdminServer
wls:/offline/base_domain/Server> cd ('AdminServer')
wls:/offline/base_domain/Server/AdminServer> ls ()
...
-rw- ListenPort 7001
...
wls:/offline/base_domain/Server/AdminServer> set ('ListenPort',7778)
wls:/offline/base_domain/Server/AdminServer> updateDomain ()
wls:/offline/base_domain/Server/AdminServer> exit ()

Now start the AdminServer and it will be listening on port 7778.

8)How to start the Node manager and verify that it is running properly?

Ans : After the Node Manager is properly configured, you can start the Node Manager by following these steps.

Go to <Middleware_Home>\wlserver_10.3\server\bin using cd command. Type startNodeManager and press Enter. 

To verify if the Node Manager is running successfully, start your Admin Server if it is not running and go to Weblogic Server console,

Navigate to Environment --> Machines --> LocalMachine --> Monitoring Tab --> Node Manager Status. It should display Reachable. 

9)How to uninstall a Directory Server Instance in GUI mode?

Ans : Launch the graphical uninstaller, as follows:

(UNIX, Linux) $ instance-dir/OUD/uninstall

(Windows)     C:\> instance-dir\OUD\uninstall.bat

Deselect any components that you do not want to remove and click Uninstall.

10)How to set ORACLE_SID ?

Ans : Type . oraenv , press enter, then type ORACLE_SID as orcl.

11)How to increase sessions, processes and transactions in Oracle 11g database?

Ans : Alter the sessions,transactions and processes by,--> At command line, type sqlplus.--> Give username as sysdba.--> Execute the following commands –   alter system set sessions=400 scope=spfile;   alter system set processes=350 scope=spfile;   alter system set transactions=440 scope=spfile;
--> Restart the Oracle instance,    shutdown immediate;   startup;--> Execute the following commands to see the updated values      select name, value from v$spparameter where name in (‘sessions’,’processes’,’transactions’);

12)Unable to start Oracle Weblogic Server because of the following message,

<BEA-141281> <unable to get file lock, will retry ...>

s  Ans: Cause: There may be two reasons why your Weblogic raises BEA-141281 exception:

1)The Weblogic Server instance is still running.

2)It was incorrectly closed.

Solution : Ensure that java process associated with weblogic server has finished.

You can find the right process by filtering by java processes (ps -e|grep java in linux).

Then kill each of the process using process id, kill <process_id>, eg: kill 19202