linux 下expect 实现自动登入smtp服务器并发送邮件

由于想实现系统运行情况监控，发现在异常后能自动登入到公司的smtp服务器，然后发送告警到指定的邮箱  在此做个笔记
经过搜罗用shell实现了下自动登入smtp服务器并发送邮件，需要linux上安装了expect

#!/usr/bin/expect -f
spawn telnet smtp.xxx.com 25
expect "])"
send "helo 163\r"
expect "250 OK"
send "auth login\r"
expect "334*"
send "用户名base64编码后\r"
#if you don't how to get your base64 encode,reference note 1 on the bottom.
expect "334*"
send "密码base64编码后\r"
expect "235*"
send "mail from:<[e-mail]>\r"
expect "250*"
send "rcpt to:<[e-mail]>\r"
expect "250*"
send "data\r"
expect "354*"
send "from:[e-mail]\r"
send "to:[e-mail]\r"
send "subject:server error\r"
send "MIME-Version:1.0\r"
send "content-type:text/plain\r"
send "服务器挂掉了\r"
send ".\r"
expect "250*"
send "quit\r"