Mail tester daemon.
Fake a SMTP server and print email to stdout.
It binds to port 25 by default, so probably you will have to sudo it. If you want to run it in a different port, pass the port number as the first argument.
$ mt # Email contents will be displayed here. $ mt 2525 # Tell mt to bind to port 2525 instead. $ mt & # Run it in the background.
You can install it using rubygems.
$ gem install mt