爲什麼不知道關於Rails的任何信息？

Question

$ ri link_to 
Nothing known about .link_to 

其實，看來ri對Rails一無所知。但是ri --list-doc-dirs顯示包含Rails文件夾：

/usr/share/ri/1.8/system 
/usr/share/ri/1.8/site 
/root/.rdoc 
/usr/lib64/ruby/gems/1.8/doc/actionmailer-2.3.5/ri 
/usr/lib64/ruby/gems/1.8/doc/actionpack-2.3.5/ri 
/usr/lib64/ruby/gems/1.8/doc/activerecord-2.3.5/ri 
/usr/lib64/ruby/gems/1.8/doc/activeresource-2.3.5/ri 
/usr/lib64/ruby/gems/1.8/doc/activesupport-2.3.5/ri 
/usr/lib64/ruby/gems/1.8/doc/cgi_multipart_eof_fix-2.5.0/ri 
/usr/lib64/ruby/gems/1.8/doc/columnize-0.3.5/ri 
/usr/lib64/ruby/gems/1.8/doc/daemons-1.0.10/ri 
/usr/lib64/ruby/gems/1.8/doc/fastthread-1.0.1/ri 
/usr/lib64/ruby/gems/1.8/doc/gem_plugin-0.2.3/ri 
/usr/lib64/ruby/gems/1.8/doc/json-1.6.3/ri 
/usr/lib64/ruby/gems/1.8/doc/linecache-0.46/ri 
/usr/lib64/ruby/gems/1.8/doc/macaddr-1.0.0/ri 
/usr/lib64/ruby/gems/1.8/doc/mime-types-1.17.2/ri 
/usr/lib64/ruby/gems/1.8/doc/mongrel-1.1.5/ri 
/usr/lib64/ruby/gems/1.8/doc/mongrel_cluster-1.0.5/ri 
/usr/lib64/ruby/gems/1.8/doc/multipart-post-1.1.4/ri 
/usr/lib64/ruby/gems/1.8/doc/postgres-0.7.9.2008.01.28/ri 
/usr/lib64/ruby/gems/1.8/doc/rack-1.0.1/ri 
/usr/lib64/ruby/gems/1.8/doc/rake-0.8.7/ri 
/usr/lib64/ruby/gems/1.8/doc/rbx-require-relative-0.0.5/ri 
/usr/lib64/ruby/gems/1.8/doc/rdoc-3.12/ri 
/usr/lib64/ruby/gems/1.8/doc/rdoc-tags-1.2/ri 
/usr/lib64/ruby/gems/1.8/doc/rest-client-1.6.7/ri 
/usr/lib64/ruby/gems/1.8/doc/ruby-debug-0.10.4/ri 
/usr/lib64/ruby/gems/1.8/doc/ruby-debug-base-0.10.4/ri 
/usr/lib64/ruby/gems/1.8/doc/sqlite3-ruby-1.2.4/ri 
/usr/lib64/ruby/gems/1.8/doc/uuidtools-2.1.1/ri 

它有什麼問題？

UPDATE

我發現這些YAML文件/usr/lib64/ruby/gems/1.8/doc/actionpack-2.3.5/ri/ActionView/Helpers/UrlHelper/的文件夾中：

button_to-i.yaml cdesc-UrlHelper.yaml current_page%3f-i.yaml link_to-i.yaml link_to_if-i.yaml link_to_unless-i.yaml link_to_unless_current-i.yaml mail_to-i.yaml url_for-i.yaml 

但在另一個系統所在的裏效果很好，文件*.ri，不*.yaml。

Answer 1

你試過運行：

gem rdoc rails 

從文檔：

Summary: 
    Generates RDoc for pre-installed gems 

Description: 
    The rdoc command builds RDoc and RI documentation for installed gems. Use 
    --overwrite to force rebuilding of documentation. 

Answer 2

我發現，安裝RI文檔的唯一可靠的方法是這樣的（即它安裝了最新的軌道則包括ri文檔）：

sudo gem install rails --pre --ri