These days preparing for Oracle EBS R12 1Z0-238 Exam, so pasting here only for my knowledge purpose...
On UNIX, Oracle E-Business Suite includes a consolidated environment file called APPS< CONTEXT_NAME>.env, which sets up both the Oracle E-Business Suite and Oracle technology stack environments. When you install Oracle E-Business Suite, Rapid Install creates this script in the APPL_TOP directory. Normally need to source the environment file prior to any upgrade-maintenance task. At that time, you can do this action from the application tier owner user.
Suppose APPL_TOP = /u01/apps/apps_st/appl
. /u01/apps/apps_st/appl/APPS< CONTEXT_NAME >.env
. /u01/apps/apps_st/appl/APPS< CONTEXT_NAME >.env
On Windows, the equivalent consolidated environment file is called %APPL_TOP%\envshell< CONTEXT_NAME >.cmd. Running it creates a command window with the required environment settings for Oracle E-Business Suite. All subsequent operations on the APPL_TOP (for example, running adadmin or adpatch) must be carried out from this window.
Similar to setting up of database environment, you can perform this action from database tier owner user.
Suppose RDBMS_ORACLE_HOME = /u01/oracle/db/tech_st/11.1.0
. /u01/oracle/db/tech_st/11.1.0/< CONTEXT_NAME >.env
. /u01/oracle/db/tech_st/11.1.0/< CONTEXT_NAME >.env
Several other key environment files are used in an Oracle E-Business Suite system.
The adovars.env file
The adovars.env file, located in $APPL_TOP/admin, specifies the location of various files such as Java files, HTML files, and JRE (Java Runtime Environment) files. It is called from the main applications environment file, < CONTEXT_NAME >.env. The adovars.env file includes comments on the purpose and recommended setting of each variable. In a Release 12 environment, adovars.env is maintained by AutoConfig, and should not be edited manually.
The adconfig.txt file
AD utility programs perform a variety of database and file management tasks. These utilities need to know certain configuration information to run successfully. This configuration information is specified when Oracle E-Business Suite is installed, and subsequently stored in the adconfig.txt file in the /admin directory.
The fndenv.env file
This file sets additional environment variables used by the Application Object Library.
For example, it sets APPLBIN as the name of the subdirectory where product executable programs and shell scripts are stored (bin). This file should not be modified: the default values are applicable for all customers. The file is located in the FND_TOP directory.
The devenv.env file
This file sets variables that let you link third-party software and your own custom-developed applications with Oracle E-Business Suite. In Release 12, this script is located in FND_TOP/usrxit, and is automatically called by fndenv.env. This allows you to compile and link custom Oracle Forms user exits and concurrent programs with Oracle E-Business Suite.