Oracle supplies some environment variables that point to specific directories in the file system. This page explains how to setup individual users so that these environment variables are always available.
Once this is done you can test the environment is set up by using the env command or typing echo $APPL_TOP at the bash prompt.
Redhat Linux - including Oracle Enterprise Linux
In the users home directory there is a file called .bash_profile (It starts with a leading dot) Put something like the following in it:
IBM Aix systems
In the users home directory is a file called .profile
Add a line like the following to the bottom of the file
R12 VISION database
' Apps Enviroment