Setting the Oracle User Environment Variables

On each node, in the installation owner user profile file, set the environment variables ORACLE_BASE and ORACLE_HOME, and ORACLE_SID; also add ORACLE_HOME/bin to the path environment variable.

Set environment variables as shown, in the following example:

export ORACLE_BASE=/u01/app/oracle
export ORACLE_HOME=/u01/app/oracle/12.2.0/dbhome_1
export ORACLE_SID=sales1

If the environment variables ORACLE_HOME and ORACLE_SID are not set, and you try to use SQL*Plus or other tools, then you receive an error message requesting that you set these variables.