SQLPLUS connection issue

Issue:

When we give "sqlplus '/as sysdba'"as oracle user.

It shows the following error message

orakdev@ebs # sqlplus '/as sysdba'

                           Insufficient privileges

Solution:

We need to add the user to the dba group.

After adding the user to dba group we can verify it using /etc/group

root@ebs # usermod -a -G dba orakdev