If the caller has appropriate privilege, the groupmod command shall modify the entry in the system group database corresponding to a group named group.
The groupmod command is a system administration utility, see Path For System Administration Utilities.
Modify the group's group ID, setting it to gid. If the -o option is not used, no other group shall have this group ID. The value of gidshall be non-negative.
Note: Only the group ID in the database is altered; any files with group ownership set to the original group ID are unchanged by this modification.
changes the name of the group from group to group_name.