The error is in the mkmf.log file. That file should be located at /home/hxh/.rvm/gems/ruby-1.9.3-p448/gems/linecache-0.46/ext/linecache/mkmf.log. If not, you can use sudo find / -name mkmf.log to find it. To troubleshoot further, see “How to install Nokogiri Ruby gem with mkmf.log saying libiconv not found?“
A fork of ruby-debug just called ‘debugger’ now exists that incorporates many of the fixes people had been deploying on top of ruby-debug19, so you should be able to just change your Gemfile to gem ‘debugger’ … and off you go.
Update (April 28, 2012) Try the new debugger gem as a replacement for ruby-debug. (credit to @ryanb) Update (March 2, 2012) Installation of linecache19 and ruby-debug-base19 can be easily done with: bash < <(curl -L https://raw.github.com/gist/1333785) (credit to @fredostarr) Original answer Have you looked at ruby-debug19 on ruby-1.9.3-preview1? Here’s a temporary solution: http://blog.wyeworks.com/2011/11/1/ruby-1-9-3-and-ruby-debug Excerpt from … Read more