Brian Schröäer said:

> I'm not really good informed, but as far as I know to use ruby gems
> you need to change the sourcecode of your program, while rpa is a real
> package installer that installs libraries into the search path. If
> this is wrong, please correct me.

This is incorrect.

You do need to assure that the rubygems package manager is loaded in order
to take advantage of any gems on your system.  There are basically three
options:

(1) Do a "require 'rubygems'" in your code.
(2) Launch the script with an explicit -rubygems on the command line
    (e.g.   ruby -rubygems your_script_name.rb)
(3) Set the RUBYOPT environment variable to be "rubygems".

(2) and (3) require no changes to a code base in order to work with gem
libraries.  I tend to use (3).

If you wish to lock down particular version of a library, then you are
free to use the require_gem command and supply an explicit version
constraint. I know that some folks using rails have done this to support
multiple versions of rails on a single server.  This is handy because
different web apps were written against different versions of rails over
time.

But if you don't need the explicit versioning, just a regular require
works just fine.

-- 
-- Jim Weirich     jim / weirichhouse.org    http://onestepback.org
-----------------------------------------------------------------
"Beware of bugs in the above code; I have only proved it correct,
not tried it." -- Donald Knuth (in a memo to Peter van Emde Boas)