type "Y" in answer to the question.
This advice is a bit dangerous. If everything has gone as expected and the program just asks whether you want to continue with the upgrade, then it's naturally all right to answer "Y". But if everything isn't all right and the program asks whether it should continue anyway, then you should type "n". Really.
Things don't go wrong when you just finished invoking "apt-get update && apt-get dist-upgrade". It they go wrong it's later, along the download process.
Precisely. The question "Do you want to continue? [Y/n] y
" comes before
the download starts (after apt-get dist-upgrade
has reported how much additional disk space it requires). But if there's something wrong with the server the program will tell you so instead and ask you whether you want to continue anyway. And if it does you should usually answer "no". If you then type "Y" instead, things will
usually go wrong during the download process that follows.