1. How to change the group of a user if the user is already exists. [oinstall to dba]
Sol: /usr/sbin/usermod -g dba oracle
2. If the oracle user exists, but its primary group is not
"oinstall" or it is not a member of the
"dba" group, then enter the following command:
Sol: /usr/sbin/usermod -g oinstall -G dba oracle