I wanted to get ferret running for a ruby on rails project. It had a few dependencies that were needed to get it working with cferret (the fast c port of parts of lucene).
So here’s what I did to get it installed. I had already installed the rubygems package from http://www.sgtpepper.net/hyspro/deb.
apt-get install ruby1.8-dev make gcc
gem install ferret
The ruby1.8-dev package will prevent “no such file to load — mkmf” errors and the other 2 allow ferret to compile the cferret code.