query yes no

gistfile1.sh

query_yesno () {
    DEFAULT="no"
    YES="y"
    NO="n"

    case $2 in
        [Yy]*) YES="Y"
               DEFAULT="yes";;
        [Nn]*) NO="N"
               DEFAULT="no";;
    esac

    while true; do
        read -p "$1 [$YES/$NO]: " yn
        if [ "$yn" = "" -a "$2" != "" ]; then
            yn=$2
        elif [ "$yn" = "" ]; then
            yn=$DEFAULT
        fi

        case $yn in
            [Yy]* ) return 0;;
            [Nn]* ) return 1;;
            * ) echo "Please answer yes or no.";;
        esac
    done
}