2.md

作业二

1. 编写一个shell脚本显示HOME、PATH、SHLVL、LOGNAME变量的值

#!/bin/sh
echo $HOME
echo $PATH
echo $SHLVL
echo $LOGNAME

2. 用while语句重写下列Shell脚本程序，以实现相同的功能：

#!/bin/sh
clear
select item in Continue Finish
do
case “$item” in
        Continue) ;;
        Finish) break ;;
        *) echo “Wrong choice! Please select again!” ;;
esac
done

改写如下:

#!/bin/sh
clear

echo "1) Continue"
echo "2) Finish"
echo -n "#? "

while read choice
do
	case $choice in
		1)echo -n "#? ";;
		2)break;;
		*)echo "Wrong choice! Please select again!"
		  echo -n "#? ";;
	esac
done

3. 编写一个shell脚本，显示Fibonacci数列的前10个数字。(Fibonacci数列: a[i+2]=a[i+1]+a[i], a[1]=0, a[2]=1, i>=1)

#!/bin/sh
COUNT=${10}
first=0
second=1
for ((i=1;i<=10;i++))
do
	echo $first
	tmp=$first
	first=$second
	second=$((tmp+second))
done