使用OS X 10.8.4
和ruby 1.9.3p194
$ gem install rails
Successfully installed rails-4.0.0
1 gem installed
Installing ri documentation for rails-4.0.0...
Installing RDoc documentation for rails-4.0.0...
ERROR: While generating documentation for rails-4.0.0
... MESSAGE: error generating /Users/michaelirey/.rvm/gems/ruby-1.9.3-p194/doc/rails-4.0.0/rdoc/guides/Rakefile.html: Error while evaluating /Users/michaelirey/.rvm/gems/ruby-1.9.3-p194/gems/rdoc-3.12.2/lib/rdoc/generator/template/darkfish/page.rhtml: undefined method `chomp' for nil:NilClass (RDoc::Error)
... RDOC args: --op /Users/michaelirey/.rvm/gems/ruby-1.9.3-p194/doc/rails-4.0.0/rdoc lib --title rails-4.0.0 Documentation --quiet
看起来这只是为了文档,但如果没有错误地安装东西仍然会很好。