--- /dev/null
+A command taking no args:
+
+ $ rbd showmapped junk
+ rbd: too many arguments
+ [1]
+
+A command taking one arg:
+
+ $ rbd info img1 junk
+ rbd: too many arguments
+ [1]
+
+A command taking two args:
+
+ $ rbd copy img1 img2 junk
+ rbd: too many arguments
+ [1]
+
+A command taking three args:
+
+ $ rbd lock remove img1 lock1 locker1 junk
+ rbd: too many arguments
+ [1]
+
+A command taking unlimited args:
+
+ $ rbd feature enable img1 layering striping exclusive-lock object-map fast-diff deep-flatten journaling junk
+ rbd: the argument for option is invalid
+ [1]
+
+ $ rbd feature disable img1 layering striping exclusive-lock object-map fast-diff deep-flatten journaling junk
+ rbd: the argument for option is invalid
+ [1]