What command is used to list all user members of a specified group?

The command getent group groupname is utilized to list all user members of a specified group by querying the system databases configured in the Name Service Switch (NSS) configuration. This command retrieves information about the group from various sources, such as local files (like /etc/group) or network databases like LDAP, if configured, ensuring a more comprehensive view of group memberships.

When executed, it provides details about the group, including its name, password (if applicable), Group ID (GID), and the list of users who are members of that group. This makes it a versatile command suitable for different environments, whether they are simple or complex user management systems.

The other options have limitations in their capabilities or contexts. For instance, using cat /etc/group would only show the contents of the local group file, not considering additional group memberships defined outside of this file. The command users groupname is not a valid command for listing group members. Lastly, while members groupname seems like it could be a command, it is not standard in most distributions without additional tools being installed.