Installing Oracle XE under Ubuntu – it’s easier than Windows..

First you have to add a repository to your sources.list

"sudo gedit /etc/apt/sources.list"

add: "deb http://oss.oracle.com/debian unstable main non-free"

Now update you repository: "sudo apt-get update"

Now execute the command to install Oracle XE: "sudo apt-get install oracle-xe"

Oracle XE will be downloaded now, you have to press Y (yes) twice to get the following message:

You’re now asked for the port numbers of Oracle Application Express (apex) and the database listener. port 8080 (web) than port 1024 (listner) default setings.

The final steps are entering a password for SYS and SYSTEM and tell the system you want to load Oracle on boot time.

Now go to http://localhost:8080/apex (or http://127.0.0.1:8080/apex) you’re ready to go.

if you need to change the default port numbers for any reason it can be done in sql-plus
(located at /usr/lib/oracle/xe/app/oracle/product/10.2.0/server/bin)

code:

SQL> begin

2 dbms_xdb.sethttpport(’8081′);

3 end;

4 /

PL/SQL procedure successfully completed.

Sources:
http://www.oracle.com/technology/tech/linux/install/xe-on-kubuntu.html
http://daust.blogspot.com/2006/01/xe-changing-default-http-port.html
http://www.oracle.com/technology/tech/linux/htdocs/oracleonlinux_faq.html