What does the 'groups' command display?

The 'groups' command is specifically designed to show the groups that a particular user is a member of in a Linux system. When executed, it provides a straightforward output listing all the groups associated with the specified user, which can be incredibly useful for managing user permissions and understanding user roles within the system.

By using the command without any arguments, the system will display the groups for the currently logged-in user. If followed by a username, it will return the group memberships for that specific user. This information helps system administrators and users themselves to identify access rights and group-based permissions, as group memberships are often leveraged for controlling user access to files and system resources.

The other options do not accurately reflect the function of the 'groups' command. For instance, it does not list all users on the system or provide a comprehensive overview of user permissions or system settings related to groups. Instead, it has a focused purpose centered around user group affiliations.