To modify an existing group on a Linux system, which command is used?

The command used to modify an existing group on a Linux system is indeed "groupmod." This command allows you to change the details of a specified group, such as its name or ID. Group modifications could involve updating the group's name or adjusting its GID (Group ID), which is crucial for managing user permissions and access rights effectively within the system.

For instance, if a group name needs to be changed to better reflect its purpose or to adhere to a new naming convention, "groupmod" facilitates this change without the need to delete and recreate the group, which would lead to potential complications such as losing group memberships or associated settings.

Understanding the roles of the other commands also helps clarify why they are not suitable for modifying an existing group. "groupadd" is specifically used for creating new groups, while "groupdel" is for deleting existing groups. The "usermod" command pertains to modifying user account information, not group details. Therefore, "groupmod" is the appropriate choice for altering an already established group, making it essential for effective user and group management in Linux environments.