How do I install Ruby with libyaml on Ubuntu 11.10?

Question

I installed ruby-1.9.3-p0 on my Ubuntu 11.10 wubi and then rubygems to get Rails set up.

This is my code:

sudo ruby setup.rb 

I got this error:

"/usr/local/lib/ruby/1.9.1/yaml.rb:56:in'<top(required)>': It seems your ruby installation is missing psych (for YAML output).  To eliminate this warning, please install libyaml and reinstall your ruby." 

I installed libyaml and reinstalled Ruby but still it doesn't work. The information changed and I have no idea what's wrong with it.

Answer 1

You must install the paquage libyaml-dev before installing ruby, if not you can still use extconf.rb for the missing library. So for this problem you can do (from the ruby install folder) :

cd ext/psych ruby extconf.rb make make install 

Extconf.rb is usefull for adding a library after have installed ruby.