Swaks - Recipes for use
    Because Swaks is a very flexible tool it can be hard to fully grasp what
    it can do (and few people want or need to). However, I have used Swaks
    in interesting ways, and others have done the same and shared them with
    me. I hate for these interesting ideas go to waste, so I am including
    them in this file.

Simple address verification
    I have had the following in my kshrc for years:

         alias vrfy='swaks -q rcpt -t'

    This allows you to quickly ask a mail server whether a recipient is
    valid (depending on how the mail server is configured, of course).
    Example output:

         g3 0 /home/jj33 > vrfy proj-swaks@jetmore.org
         === Trying mx2.balanced.spacey.mail.dreamhost.com:25...
         === Connected to mx2.balanced.spacey.mail.dreamhost.com.
         <-  220 spaceymail-mx3.g.dreamhost.com ESMTP
          -> EHLO g3.jetmore.net
         <-  250-spaceymail-mx3.g.dreamhost.com
         <-  250-PIPELINING
         <-  250-SIZE 40960000
         <-  250-ETRN
         <-  250-STARTTLS
         <-  250 8BITMIME
          -> MAIL FROM:<jj33@g3.jetmore.net>
         <-  250 Ok
          -> RCPT TO:<proj-swaks@jetmore.org>
         <-  250 Ok
          -> QUIT
         <-  221 Bye
         g3 0 /home/jj33 >

    This is a valid email (the mail server returned 250 in response to my
    RCPT request). This is fairly verbose though. Note the "0" in my command
    prompt is the exit status of the last command ($?). Since Swaks tries to
    be good about setting a useful return value, I could make vrfy totally
    silent:

         g3 0 /home/jj33 > alias vrfy='swaks -q rcpt --silent 3 -t'
         g3 0 /home/jj33 > vrfy proj-foobar@jetmore.org
         g3 24 /home/jj33 > vrfy proj-swaks@jetmore.org
         g3 0 /home/jj33 >

    As you can see by the $? output, proj-foobar is not a valid address and
    proj-swaks is.

    This works well if you use $? in your command prompt, but if not it is
    less useful. Also, it loses potentially useful information the mail
    server might provide when rejecting an address. To get around this, try
    using --silent 2, which prints only errors. Now you can expect no output
    to mean the mail was valid, and any other output to mean an error
    occurred:

         g3 0 /home/jj33 > PS1=$HOST' $PWD > '
         g3 /home/jj33 > alias vrfy='swaks -q rcpt --silent 2 -t'
         g3 /home/jj33 > vrfy proj-foobar@jetmore.org
         <** 550 <proj-foobar@jetmore.org>: Recipient address rejected: User unknown in virtual alias table
         g3 /home/jj33 > vrfy proj-swaks@jetmore.org
         g3 /home/jj33 >

Stress-testing an SMTP server
    I've received a couple of different requests and a couple of different
    patches over the years to add functionality to have Swaks fork and send
    a bunch of emails to a single address. I may still add this
    functionality some day, but I still feel pretty strongly that ultimately
    Swaks core is a single transaction. Forking multiple Swaks seems just
    outside the scope of the tool.

    However, this does seem to be something people want to do. To that end,
    here is a quick-and-dirty shell script that is (almost) a drop in
    replacement for Swaks:

         #!