doubt while installing oracle db in linux

[muzu1232004]

What is the meaning of a group in linux ?
why do we add the groups named as dba,oinstall,op er and
also a user before installing the oracle software on linux machine ?
Can any one explain me the understanding of this ?

[amitpatel66]

GROUPS are created for security purpose. U create a GROUP,u assign certain priviliges to that GROUP so that the members of that GROUP will have those privileges. GROUP DBA will have SYSADMIN privileges where then ca do all DBA operations and GROUP user will have certain priviliges for the USERS.

[debasisdas]

That is basically done to define roles of differnet users.