#!/bin/bash
flag1=0 # 确认用户名是否被注册过的标识
user_file="/root/user.txt"
echo "欢迎来到注册登录系统！"
while true
do
    read -p "请输入你的选择，1为登录，2为注册,q为退出:" select
    if [ ${select} == "1" ]
        then
        echo "登录"
    elif [ ${select} == "2" ]
        then 
        echo "注册"
        # 接受注册的账号的循环
        while true
        do
            read -p "请输入你要注册的账号:" username
            while read line
            do
                user=`echo ${line}|awk -F':' '{print $1}'`
                flag1=0
                if [ $username == $user ]
                    then
                    echo "用户名已经存在，请换一个用户名！"
                    flag1=1
                    break
                fi
            done < ${user_file}
            if [ $flag1 == 1 ] 
                then
                continue          
            fi
            break
        done
        # 接收注册的密码的循环
        while true
        do
            read -p "请输入你注册的密码:" passwd1
            read -p "请再次输入你的密码:" passwd2
            if [ $passwd1 == $passwd2 ]
                then
                echo "注册成功"
                echo "${username}:${passwd1}" >> ${user_file}
                break
            else
                echo "两次密码输入不一致"
                continue
            fi
        done
    elif [ ${select} == "q" ]
    then 
        break
    else
        echo "输入有误"
    fi
done