错误：sh: sendmail: not found
解决：sudo apt-get install sendmail
sendmail重启 停止 启动：
/etd/init.d/sendmail restart
/etd/init.d/sendmail stop
/etd/init.d/sendmail start
错误：sh: sendmail: not found
解决：sudo apt-get install sendmail
sendmail重启 停止 启动：
/etd/init.d/sendmail restart
/etd/init.d/sendmail stop
/etd/init.d/sendmail start
![sudo apt-get update 出错 Updating from such a repository can‘t be done securely, and is therefore[图]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=)