Linux上case用法

#!/bin/bash
# This is a script for test case
ASK_COUNT=$1            #从参数获取该变量的值
#
if [ -z "$ASK_COUNT" ]    #判断ASK_COUNT变量是否为空,为空输出1,不为空输出2
then
        echo "1"
else
        echo "2"
fi
echo "ASK_COUNT:$ASK_COUNT"
case $ASK_COUNT in
2)
        echo
        echo "Please answer the question."
        echo
;;
3)
        echo
        echo "One last try... Please answer the question."
        echo
;;
4)
        echo
        echo "Since you refuse to answer the question..."
        echo
        #
        exit
;;
esac　　# shell 的风格，用倒序的字母单词和 正序的单词配对。比如 if 语句， 结束时用 fi 来配对
# 

[keysystem@localhost 20180202]$ sh case_test.sh 2
2
ASK_COUNT:2

Please answer the question.

[keysystem@localhost 20180202]$ sh case_test.sh 3
2
ASK_COUNT:3

One last try... Please answer the question.

[keysystem@localhost 20180202]$