1. 编写以下脚本、执行，说明脚本功能。
$ vi reverse.sh
if [ $# -ne 1 ]
then
echo "Usage: $0 number"
echo " I will nd reverse of given number"
echo " For eg. $0 123, I will print 321"
exit 1
n=$1
rev=0
sd=0
while [ $n -gt 0 ]
do
sd=`expr $n % 10`
rev=`expr $rev \* 10 + $sd`
n=`expr $n / 10`
done
echo "Reverse number is $rev"
功能：
将输入的一串数字倒序输出。
首先判断是否带参，如果不带输出错误提示。
然后将输入参数倒序输出。
2. Write a shell script to print the information as to how many files and how many
directories are present in your home directory.
