#!/bin/bash
# chk_root.sh
#
echo test my computer is or not safety  #显示“ test my computer is or not safety  ”
root_num=`awk -F: '{print $3}' /etc/passwd|grep "^0"|wc -l`  #以“：”为分隔符，打印出/etc/passwd文件中第三个域的字段，并grep以“0”开头的（意思是UID是0的用户）,然后计算
行数(3行代表有3个UID为0的用户，包括root)，最终赋值给root_num.
if [ $root_num -eq 1 ];then  #如果$root_num的值为1，表示只有一个root用户
echo your computer is safety #显示“ your computer is safety ”
else  #否则
awk -F: '{print $3,$1}' /etc/passwd|grep "^0"|grep -v "root" >> hack1 #打印/etc/passwd中的第三个域（UID）和第一个域（用户名），并且grep以“0”开头的行，输出到hack1的文
件中
cat hack1|awk '{print $2}'>>hack  #查看hack1文件的内容，并打印出第二个域的内容，输出到hack文件中
for number in `cat hack`   #查看hack的内容，并循环赋值给number
do
echo $number mybe created by hacker.  #显示“ xxx mybe created by hacker.”
read -p "are you want to delete it? y or n  :" answer #显示“are you want to delete it? y or n  :“
if [ $answer = "y" ] #如果回答是”y“
then
userdel -r $numeber  #删除xxx
echo $number is delete. #显示”xxx is dele“
if [ $answer = "yes"]  #如果回答是”yes“
then
userdel -r $number 
echo $number is delete.
fi
fi
done
fi
rm -f hack*  #删除hack和hack1文件