linux中与test命令相同功能的[] __demo

#!/bin/bash
#Program:
#               This program shows "Hello World!" in your screen.
#History
#       2015/12/09

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

read -p "please input (Y/N) : " flg

[ "$flg" == "y" -o "$flg" == "Y" ] && echo "OK,continue" && exit 0
[ "$flg" == "n" -o "$flg" == "N" ] && echo "Oh,interrupt!" && exit 0
echo "I don't know what your choice is" && exit 0