Using Linux Groups

User accounts are great for controlling security for individual users, but they aren't so good at allowing groups of users to share resources. To accomplish this, the Linux system uses another security concept, called groups.

Group permissions allow multiple users to share a common set of permissions for an object on the system, such as a file, directory, or device (more on that later in the “Decoding File Permissions” section).

Linux distributions differ somewhat on how they handle default group memberships. Some Linux distributions create just one group that contains all of the user accounts as members. You need to be careful if your Linux distribution does this, as your files may be readable by all other users on the system. Other distributions create a separate user account for each user to provide a little more security.