Usage:
-unittypename set [string]
OR
-unittypename [unit id]

Using [set] [string] will set the name to be used for the command. Using [unit id] will change the name of ALL units of that type to what you had previously set.

Examples:
-unittypename set Bad Grunt
(Sets the name to be used to Bad Grunt)

-unittypename ogru
(If the previous example was used, then all Grunts will now be named "Bad Grunt")