Replying to myself: it turned out that I was using the wrong way to
check if I can require the given gem, and actually rubygems works just
fine. This transformed my problem into another question. What's the
difference between the following two cases?

$ ruby -rsome-gem -e 'puts "ok"'
ruby: no such file to load -- some-gem (LoadError)
$ ruby -e 'require "some-gem"; puts "ok"'
ok
$

mortee wrote:
> Hi,
> 
> I have a problem with rubygems on a OS X 10.4.10 Tiger PPC. Ruby 1.8.6
> and rubygems 0.9.4 are installed properly. Ruby is installed through
> fink so I set PREFIX to /sw. I installed rubygems by
> 
> PREFIX=/sw
> export GEM_HOME=$PREFIX/lib/ruby/gems/1.8
> export RUBYLIB=$PREFIX/lib/ruby:$PREFIX/lib/site_ruby/1.8
> sudo ruby setup.rb all --prefix=$PREFIX
> 
> so it should be aware of the repository path. I installed some gems, the
> gem list command shows them as expected.
> 
> I have -rubygems in RUBYOPT.
> 
> But when I simply require any gem by name, I get a LoadError (on the
> file, not rubygems itself). If I specify the absolute path of the gem's
> main file to require, it passes without error.
> 
> What may be wrong with my setup?
> 
> thx
> mortee
> 
> 
>