How to create an exit message

The abort function does this. For example:

abort("Message goes here")

Note: the abort message will be written to STDERR as opposed to puts which will write to STDOUT.

If you want to denote an actual error in your code, you could raise a RuntimeError exception:

raise RuntimeError, 'Message goes here'

This will print a stacktrace, the type of the exception being raised and the message that you provided. Depending on your users, a stacktrace might be too scary, and the actual message might get lost in the noise. On the other hand, if you die because of an actual error, a stacktrace will give you additional information for debugging.

I've never heard of such a function, but it would be trivial enough to implement...

def die(msg)
  puts msg
  exit
end

Then, if this is defined in some .rb file that you include in all your scripts, you are golden.... just because it's not built in doesn't mean you can't do it yourself ;-)