sendmail.rb

require 'tlsmail'
require 'time'

from = "[email protected]"
to = "[email protected]"
p = "password"
content = <<EOF
From: #{from}
To: #{to}
subject: TEST from ruby
Date: #{Time.now.rfc2822}

Hello world!
EOF

Net::SMTP.enable_tls(OpenSSL::SSL::VERIFY_NONE)
Net::SMTP.start('smtp.gmail.com', 587, 'gmail.com', from, p, :login) do |smtp|
    smtp.send_message(content, from, to)
end