until loop that prompts for a valid response

[vergeb]

I am trying to write an until loop that will only exit when a valid response (Y/N) is given. for example:
until
[[ $response == "Y" ]] or [[ $response == "N" ]]
do
read response?"Enter response "
if
then
else
fi
done

Any ideas on how to make this work?

 

[olded]

#!/bin/ksh

until [[ $response == "Y" ]] || [[ $response == "N" ]]
do
echo "Enter response "
read response
echo $respone
done