Requirrement : client wants to have two portal server 220.127.116.11 instances on single linux box with existing WAS.
Here is the following steps to achieve.
* Install the first portal instance on your linux box. Here is a link.
* Varify your installaton by hitting the portal URL as well as application console URL.
* Before installing second Portal Server instance make sure that all the applications on that linux box have been started so as to avoid any port conflicts.
* This second portal installation will be using an existing WebSphere directory with an existing instance of WebSphere Application Server.
* run the following command on the terminal.
./install.sh -console -W globalInstall.active=false -W was.undetectedWas="/opt/ibm/WebSphere" -W globalInstall.location=/opt/ibm/WCM -W wasLocationExistsSequence.active=false -W detectProfileAction.profileName="wcm_profile" -W detectProfileAction.profilePath=/opt/ibm/WebSphere/wcm_profile -W invalidProfileExit.active=false
Note: The directory that is specified for globalInstall.location cannot already contain an installation of Portal. If Portal exists in the desired directory, the EJPIC0054E exception occurs and a new unique directory (WCM in this case) must be used. However, even in this case, the existing installation of WebSphere Application Server can still be used with Portal. In addition, the directory specified by detectProfileAction.profilePath cannot exist prior to installation.
* Enter the appropriate values when prompted and check for the successfull installation.
Here is a technote from IBM which will help you in troubleshooting any problem you face during this procedure.