No further input is given on the user side as to why the format is incorrect. Obviously if user guide is read, then perhaps they might understand eventually. In the case that delete r/ is reading "delete r" as a new command, it is understandable that its not able to recognise what command it is. However, just 'format is incorrect' is quite vague and perhaps you could include 'refer to help guide, or type help' as a better way of handling such unknown input, like you do for the general message you show which is 'Invalid command type. Please refer to user guide for full list of commands.'
In the case that it is indeed detecting delete but incorrect format is rightfully detected, include format for delete maybe.
No further input is given on the user side as to why the format is incorrect. Obviously if user guide is read, then perhaps they might understand eventually. In the case that delete r/ is reading "delete r" as a new command, it is understandable that its not able to recognise what command it is. However, just 'format is incorrect' is quite vague and perhaps you could include 'refer to help guide, or type help' as a better way of handling such unknown input, like you do for the general message you show which is 'Invalid command type. Please refer to user guide for full list of commands.'
In the case that it is indeed detecting delete but incorrect format is rightfully detected, include format for delete maybe.