clarify udevinfo device walk

@@ -148,7 +148,14 @@
 		retval = -1;
 		goto exit;
 	}
-	printf("\ndevice '%s' has major:minor %s", class_dev->path, attr->value);
+
+	printf("\nudevinfo starts with the device the node belongs to and then walks up the\n"
+	       "device chain to print for every device found all possibly useful attributes\n"
+	       "in the udev key format.\n"
+	       "Only attributes within one device section may be used in a rule to match the\n"
+	       "device for which the node will be created.\n"
+	       "\n");
+	printf("device '%s' has major:minor %s", class_dev->path, attr->value);
 	sysfs_close_attribute(attr);
 
 	/* open sysfs class device directory and print all attributes */