Ruby Student wrote:
>> /usr/local/bin/ruby extconf.rb
>> *** extconf.rb failed ***
>> ruby -v
>> *ruby 1.9.2p180 (2011-02-18 revision 30909) [x86_64-linux]*

Kristofer White <me / kmwhite.net> wrote:
> Do, in a terminal, the following:
>
> rpm -qa | grep ruby
>
> That will tell you all RPMs installed that have 'ruby' in their name.

In this case, that likely won't help because he is not using Red Hat's
ruby package, but some other Ruby in /usr/local (while it could be
from a 3rd-party RPM, it's probably a source install).

Ruby Student, you installed ruby through something like "./configure
&& make && make install"?