if user input number (bash)

if_input_number.sh

    read -n 1 -p "Would you like to install 
                1. AAAA
                2. BBBB
                3. CCCC
                4. DDDD 
                
                Please select (1/2/3/4) " ans;

    echo " "
    case $ans in
        1)
            echo "install AAAA";;
        2)
            echo "install BBBB";;
        3)
            echo "install CCCC";;
        4)
            echo "install DDDD";;
        *)
            echo "Unknown"
            exit;;
    esac

result

hoshina@hoshina-ThinkPad-X1-Carbon-7th:~$ bash if_input_number.sh 
Would you like to install 
                1. AAAA
                2. BBBB
                3. CCCC
                4. DDDD 
                
                Please select (1/2/3/4) 2 
install BBBB