#!/bin/bash

echo "please input y/n"
read yn

case $yn in
    # | 表示或的意思
    y|Y|yes|Yes|YES)
        echo "your input yes ..."
        ;;
    n)
        echo "your input no ..."
        ;;
    *)
        echo "your input is invalid argument"
        exit 1
esac

# if [ "$yn" = "y" ]; then
#     echo "your input yes ..."
# elif [ "$yn" = "n" ]
# then
#     echo "your input no ..."
# else
#     echo "your input is invalid argument"
# fi