Lists the groups to which the user belongs seperated by the \',\' delimiter. The first on group on the list is the primary group. Groups are collections of users that can share access authority to protected resources. Groups can be formed for users who access the same applications or hardware resources, perform similar tasks, or have similar needs for information. A user can be a member in up to 32 groups. However, only one primary group for a user can be specified. When a new user account is created and the primary group is not provided, the system assigns the user to the primary default group specified in the /usr/lib/security/mkuser.default file.