go build

./sendemailgo --help

Usage of ./sendemailgo:
  -f string
        from (sender) email address.
  -h    display the usage and exit.
  -help
        display the usage and exit.
  -m string
        message body.
  -p int
        the mail server port, default 25. (default 25)
  -s string
        the mail server address.
  -t string
        to email address(receiver).
  -tls
        enable the tls option.
  -u string
        message subject.
  -v    display the version and exit.
  -version
        display the version and exit.
  -xp string
        password for SMTP authentication.
  -xu string
        username for SMTP authentication.

    ./sendemailgo -f [email protected] -s smtp.example.com -xu [email protected] -xp password -t [email protected]　-u "Test" -m "Test mail"