groupmod(8) on Linux
The text 0f860c1a1a84, as Debian 8 (Jessie) shipped it.
modify a group definition on the system
Flags it lists
-
--gid -
--help -
--new-name -
--non-unique -
--password -
--root -
-R -
-g -
-h -
-n -
-o -
-p