#!/bin/bash

# Program:

#    This program shows the user's choice

# History:

#//

PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin:~/bin&

export PATH

read -p "Please input (Y/N): " yn

[ "$yn" == "Y" -o "$yn" == "y" ] &&echo "OK, continue" && exit0

[ "$yn" == "N" -o "$yn" == "n" ] &&echo "Oh, interrupt!" && exit0

echo "I don't know what your choice is"&& exit 

Please input (Y/N): y

[: : y: unexpected operator

[: : y: unexpected operator

I don't know what your choice is