User groups play an important role on Linux systems. They provide an easy way for a select groups of users to share files with each other. They also allow sysadmins to more effectively manage user privileges, since they can assign privileges to groups rather than individual users.
While a user group is generally created whenever a user account is added to a system, there’s still a lot to know about how they work and how to work with them.
One user, one group?
Most user accounts on Linux systems are set up with the user and group names the same. The user “jdoe” will be set up with a group named “jdoe” and will be the only member of that newly created group. The user’s login name, user id, and group id will be added to the /etc/passwd and /etc/group files when the account is added, as shown in this example: