Groups are used for organizing users. A group is a collection of accounts with shared permissions. However, a group must exist before a user is added to that group. There are multiple commands that can be used to manage group accounts in CentOS 7. This section covers only the most popular commands available in CentOS 7 to manage local group accounts.
Control of group membership is managed with the /etc/group file. It lists the group, along with its members.