linux shell if语句

#!/bin/bash
 
read -p "please input Y/N"   keyWord
 
if [ "$keyWord" == "Y" ] || [ "$keyWord" == "y" ] ; then
    echo 'OK...countinue'
fi
 
if [ "$keyWord" == "N" ] || [ "$keyWord" == "n" ] ; then
    echo 'Oh interrupt'
fi
 
read -p "input a number : " num
 
if [ "$num" == "" ] ; then #分号面有空格是对的，没有空格也是对的，同理分号与then之间也一样。
    echo '--- A ---'
elif [ "$num" == "" ];then #
    echo '--- B ---'
else
    echo '--- C ---'
fi