From: Randy Kramer <rhkramer@...>
Date: 2006-03-18T22:19:52+09:00
Subject: How to write a Ruby service(?)?

I need to write what might be called a Ruby service or server(?)--a Ruby 
program that:
   * runs only one instance even if "invoked" multiple times
   * can be sent additional "commands" via CLI commands, e.g., if the name of 
the program is, for example, "program" I can issue multiple CLI commands 
like:
   
program <parameters>

If program is not running, it will start and perform appropriate actions based 
on the parameters.

If program is running, the existing instance of the program will receive those 
parameters and perform appropriate actions.

At the moment (and maybe permanently ;-) I'm drawing a blank as to what a 
program like that is called (service, server, ...?), and where to dig to 
learn how to implement such a thing (preferably in Ruby).

Hints?

Initially I plan to implement this under Linux--some day it may get ported to 
Windows, etc.

Thanks!
Randy Kramer

Incidentally, if the program crashes, the next invocation of the program will 
restart it and recover as much of the previous "context" as possible (which 
is, of course, only what has been recorded to disk).