最近在学习python，其中有个作业要求用python写个用户登录接口，大体完成功能有：
1、用户如果输入正确的用户名和密码，在显示登录成功
2、用户如果输入错误的用户名则显示无效用户名
3、如果密码错误，让其重试三次，三次以后则进行锁定
本脚本是我通过shell脚本实现的相应功能，仅供后续通过python实现参考。

#!/bin/bash

userfile=/root/aa
lockfile=/root/lk


read -p "Please input your username:" user
read -p "Please input your password:" pass


if [ -z ${user} ] || [ -z ${pass} ];then
   echo "Username or Password is not allowed null"
   exit
fi

chk_user=`cat ${userfile}|awk '{print $1}'|egrep -iw ${user} |wc -l`
chk_lk=`cat ${lockfile}|egrep -iw ${user} |wc -l`

if [ ${chk_lk} -ne 0 ] && [ ${chk_user} -eq 1 ] ;then
   echo "${user} locked "
   exit
fi

while read line
#for line in `cat ${userfile}`
do
    username=`echo $line |egrep -iw "${user}"|awk '{print $1}'`
    password=`echo $line |egrep -iw "${user}"|awk '{print $2}'`
    if [ ! -z ${username} ] && [ ${username} == ${user} ];then
       break
    elif [ ! -z ${user} ] && [ -z ${username} ] && [ ${chk_user} -eq 1 ] ;then
       continue
    else
       echo "Invalid username ${user}"
       exit
    fi
done < ${userfile}

if [ ${username} == ${user} ] && [ ${password} == ${pass} ];then
    echo "${username} login success"
elif [ ${username} == ${user} ] && [ ${password} != ${pass} ];then
    echo "Invalid password"
    count=0
    while [[ ${count} -lt 2 ]]
    do
       read -p "Please input your password:" pass
       if [ ${password} == ${pass} ];then
             echo "${username} login success"
             break
       else
             count=$((${count}+1))
       fi
       if [ ${count} -eq 2 ];then
          echo ${user} >> ${lockfile}
          echo "User is locked now,please contact the administrator !"
       fi
    done
else
    echo "Invalid User ${username}"
fi