merge branch 'pr-1158'

Closes #1158
LGTMs: @hqhq @cyphar

spec.go

@@ -65,6 +65,9 @@ container on your host.`,
 		},
 	},
 	Action: func(context *cli.Context) error {
+		if err := checkArgs(context, 0, exactArgs); err != nil {
+			return err
+		}
 		spec := specs.Spec{
 			Version: specs.Version,
 			Platform: specs.Platform{