require 'net/smtp'

message = <<MESSAGE_END
From: Private Person <me@fromdomain.com>
To: A Test User <test@todomain.com>
Subject: SMTP e-mail test

This is a test e-mail message.
MESSAGE_END

Net::SMTP.start('localhost') do |smtp|
 smtp.send_message message, 'me@fromdomain.com', 
               'test@todomain.com'
end

Net::SMTP.start('mail.your-domain.com')

Net::SMTP.start('mail.your-domain.com', 
        25, 
        'localhost', 
        'username', 'password' :plain)

require 'net/smtp'

message = <<MESSAGE_END
From: Private Person <me@fromdomain.com>
To: A Test User <test@todomain.com>
MIME-Version: 1.0
Content-type: text/html
Subject: SMTP e-mail test

This is an e-mail message to be sent in HTML format

<b>This is HTML message.</b>
<h1>This is headline.</h1>
MESSAGE_END

Net::SMTP.start('localhost') do |smtp|
 smtp.send_message message, 'me@fromdomain.com', 
               'test@todomain.com'
end

require 'net/smtp'

filename = "/tmp/test.txt"
# Read a file and encode it into base64 format
filecontent = File.read(filename)
encodedcontent = [filecontent].pack("m")  # base64

marker = "AUNIQUEMARKER"

body =<<EOF
This is a test email to send an attachement.
EOF

# Define the main headers.
part1 =<<EOF
From: Private Person <me@fromdomain.net>
To: A Test User <test@todmain.com>
Subject: Sending Attachement
MIME-Version: 1.0
Content-Type: multipart/mixed; boundary=#{marker}
--#{marker}
EOF

# Define the message action
part2 =<<EOF
Content-Type: text/plain
Content-Transfer-Encoding:8bit

#{body}
--#{marker}
EOF

# Define the attachment section
part3 =<<EOF
Content-Type: multipart/mixed; name=\"#{filename}\"
Content-Transfer-Encoding:base64
Content-Disposition: attachment; filename="#{filename}"

#{encodedcontent}
--#{marker}--
EOF

mailtext = part1 + part2 + part3

# Let's put our code in safe area
begin 
 Net::SMTP.start('localhost') do |smtp|
   smtp.sendmail(mailtext, 'me@fromdomain.net',
             ['test@todmain.com'])
 end
rescue Exception => e 
 print "Exception occured: " + e 
end