SHELL脚本，执行有问题

set_menu_choice() {
clear
echo "Options :-"
echo
echo "   a) Add new CD"
echo "   f) Find CD"
echo "   c) Count the CDs and tracks in the catalog"
echo
echo -e "Please enter choice the press return \c"
read menu_choice
return
}

echo "Mini CD manager"
sleep 1

quit=n

while [ "$quit" != "y" ]
do
    set_menu_choice
    case "$menu_choice" in
        q | Q) quit=y;;
        *) echo "Sorry, choice not regconized";;
    esac
done
echo "Finished"
exit 0

当输入q的时候，能够正常退出；可是当输入其他字符，却不能正常匹配第二个星号选项

请看看是什么原因导致呢？~初学者，请指教