shell中exit 0和exit 1的区别有哪些

　　#/bin/bash

　　function check_extern_input() {

　　read param

　　if [ "${param}" == "exit 0" ];then

　　echo "successful exit process right now!"

　　exit 0

　　elif [ "${param}" == "exit 1" ];then

　　echo "failed exit process right now!"

　　exit 1

　　elif [ "${param}" == "return 0" ];then

　　echo "func normal return, process not exit, Enter go on..."

　　return 0

　　else

　　echo "Input again:"

　　fi

　　}

　　while true ; do

　　check_extern_input

　　done