While installing Oracle 12c, following error is observed
OUI was not able get the OS Group of the user which is used to install Oracle binaries, since /etc/group did not have proper permission.
Make sure the installation user has read privilege to the file : /etc/group
Default permission found on Unix systems
To determine whether the oracle user exists and belongs to the correct groups, enter the following command:
If the oracle user exists, then this command displays information about the groups to which the user belongs. The output should be similar to the following, indicating that oinstall is the primary group and dba is a secondary group: