shell read

#! /bin/sh
while : # loop
do
    if read -t 5 -n 1 -p "Do you want to update Recovery [Y/N]:" #limited time 5s
    then
    case $REPLY in
    Y|y)
        echo -e "\n input $REPLY\n"
    break
    ;;
    N|n)
        echo -e "\n input $REPLY\n"
    break
    ;;
    *)
        echo -e "\n input parameter error !! \n"
    continue
    esac
    else #timeover
        echo -e "\n take silence as input N\n"
        break
    fi
done