注意：若直接复制的的话脚本内容格式会非常乱解决方法

1.Esc
2.光标到开头Ctrl+v
3.上下键选中所有
4.按=即可恢复正确格式
注：脚本内容cat追加部分：cat与最后一个EOF需顶格,自行手动修改

注：此脚本逻辑有部分地方有bug，下一篇文章更完善

#!/bin/bash
sum=30      #初始余额总数
msg=15      #发一条短信需要15分

menu () {
cat << EOF

当前余额为$sum 分,每条短信需要$msg 分

==========================
1.充值
2.发消息
3.退出
==========================
EOF
}


recharge () {
    read -p "请输入充值金额：" money
    expr $money + 1 &>/dev/null
    if [ $? -eq 0 ]
    then
        ((sum=$sum+$money))
        echo "充值成功，剩余余额为：$sum"
        main
    else
        ec
        echo "请输入要充值的正确的金额(正整数)！"
        recharge
    fi
}
ec () {
    echo " "
}

note () {
    read -p "输入要发送的内容：" note
    ((sum=$sum-$msg))
    echo "发送成功，余额剩余：$sum"
}

yno () {
    read -p "请问是否继续发送(yes/no)：" yno
    ec
    if [ "$yno" == "yes" ]
    then
        note
    elif [ "$yno" == "no" ]
    then
        exit 0
    else
        echo "请输入(yes或者no)"
        yno
    fi
}

panduan () {
    read -p "是否充值(yes/no):" yn
    ec
    if [ "$yn" == "yes" ]
    then
        recharge
    elif [ "$yn" == "no" ]
    then
        exit 0
    else
        echo "请输入(yes或者no)"
        panduan
    fi
}

news () {
    if [ $sum -lt 15 ] 
    then
        echo "余额不足$msg，请充值"
        panduan
    else
        while true
        do
            if [ $sum -lt 15 ] 
            then
                echo "余额不足$msg，如想发送短信请充值"
                panduan
            else
                ec
                read -p "输入要发送的内容：" note
                ((sum=$sum-$msg))
                echo "发送成功，余额剩余：$sum"
                ec
                yno
                if [ $sum -lt $msg ]
                then
                    ec
                    echo "余额不足，剩余$sum分"
                    panduan
                fi
            fi
        done
    fi
}

main () {
    while true
    do
        menu
        ec
        read -p "请选择要做的操作：" a
        sleep 1
        clear
        case $a in
            1)
                recharge
                ;;
            2)
                news
                ;;
            3)
                exit 0
                ;;
            *)
                echo "输入错误,请输入正确的选项"
        esac
    done
}
main

实现信息发送发邮件下面

#!/bin/bash
sum=30      #初始余额总数
msg=15      #发一条短信需要15分
mails=`cat /etc/mail.rc |wc -l`

menu () {
cat << EOF

当前余额为$sum 分,每条短信需要$msg 分

    ==========================
    1.充值
    2.发消息
    3.退出
    ==========================
EOF
}


recharge () {
    read -p "请输入充值金额：" money
    expr $money + 1 &>/dev/null
    if [ $? -eq 0 ];then
        ((sum=$sum+$money))
        echo "充值成功，剩余余额为：$sum"
        main
    else
        ec
        echo "请输入要充值的正确的金额(正整数)！"
        recharge
    fi
}
ec () {
    echo " "
}


mail () {
    if [ $mails -lt 70 ];then
        cat >>/etc/mail.rc<< EOF
set from=xxxxxxx@163.com smtp=smtp.163.com smtp-auth-user=xxxxxxx smtp-auth-password=xxxxxxxxxxxxxx smtp-auth=login
EOF
    else
        :
    fi
}

note () {
    mail
    read -p "输入要发送的内容：" note
    ((sum=$sum-$msg))
    echo $note >/tmp/youjian.txt
    mailx -s "短信" xxxxxxxxxx_idc@126.com </tmp/youjian.txt
    echo "发送成功，余额剩余：$sum"
}

yno () {
    read -p "请问是否继续发送(yes/no)：" yno
    ec
    if [ "$yno" == "yes" ];then
        note
    elif [ "$yno" == "no" ];then
        exit 0
    else
        echo "请输入(yes或者no)"
        yno
    fi
}

panduan () {
    read -p "是否充值(yes/no):" yn
    ec
    if [ "$yn" == "yes" ];then
        recharge
    elif [ "$yn" == "no" ];then
        exit 0
    else
        echo "请输入(yes或者no)"
        panduan
    fi
}

news () {
    if [ $sum -lt 15 ];then
        echo "余额不足$msg，请充值"
        panduan
    else
        while true
        do
            if [ $sum -lt 15 ];then
                echo "余额不足$msg，如想发送短信请充值"
                panduan
            else
                ec
                note
                ec
                yno
                if [ $sum -lt $msg ];then
                    ec
                    echo "余额不足，剩余$sum分"
                    panduan
                fi
            fi
        done
    fi
}

main () {
    while true
    do
        menu
        ec
        read -p "请选择要做的操作：" a
        sleep 1
        clear
        case $a in
            1)
                recharge
                ;;
            2)
                news
                ;;
            3)
                exit 0
                ;;
            *)
                echo "输入错误,请输入正确的选项"
        esac
    done
}
main