How do I prompt for Yes/No/Cancel input in a Linux shell script?

Question

I want to pause input in a shell script, and prompt the user for choices.
The standard Yes, No, or Cancel type question.
How d

Answer 1

In response to others:

You don't need to specify case in BASH4 just use the ',,' to make a var lowercase. Also I strongly dislike putting code inside of the read block, get the result and deal with it outside of the read block IMO. Also include a 'q' for quit IMO. Lastly why type 'yes' just use -n1 and have the press y.

Example: user can press y/n and also q to just quit.

ans=''
while true; do
    read -p "So is MikeQ the greatest or what (y/n/q) ?" -n1 ans
    case ${ans,,} in
        y|n|q) break;;
        *) echo "Answer y for yes / n for no  or q for quit.";;
    esac
done

echo -e "\nAnswer = $ans"

if [[ "${ans,,}" == "q" ]] ; then
        echo "OK Quitting, we will assume that he is"
        exit 0
fi

if [[ "${ans,,}" == "y" ]] ; then
        echo "MikeQ is the greatest!!"
else
        echo "No? MikeQ is not the greatest?"
fi