I recently upgrade to the 10.10 Yosemite beta, but I'm having trouble getting Nokogiri installed. I'm using RVM and Ruby 1.9.3. I've also followed the steps here and tried following the instructions on Nokogiri's homepage. I've installed libxml2 (2.9.1) and libxslt (1.1.28) via homebrew, and have tried using the command line tools from both my Xcode 5 install and Xcode 6 beta. gem install nokogiri