In many cases the dialog asks for a confirmation and is looking for a ``yes'' or ``no''. In these cases the prompt appears like:
Sorting block, sure (yes, No, ignore-case):
The acceptable responses are the first letter of each of the words enclosed in the ()s. In each case one of the words begins with a capital letter (in the above, No). The capitalized letter is the default response--this means that if you do not press [n] or [i] Ved assumes you have entered [N].
The defaults have been chosen so that pressing [Enter] or [Space] is always a safe response. If you are going to do something which will change your data, you will need to press a specific key.