anchor.diff:   $ gem update asciidoctor
   
   [TIP]
  -====
  +--
   If you accidentally use +gem install+ instead of +gem update+ then you will have both versions installed.
   If you wish to remove the older version use the +gem+ command:
   
    $ gem cleanup asciidoctor
  -
  -====
  +--
   
   On Fedora, you can update it using:
   
  
positive.code: 
  == Operating Systems
  
  Asciidoctor works on Linux, Mac and Windows.
  
  == Dependency and Configuration Requirements
  
  
negative.code: --
  To render a file containing AsciiDoc markup to HTML 5, use:
  
  [source]
  Asciidoctor.render_file 'sample.adoc', :in_place => true
  
  The command will output to the file +sample.html+ in the same directory.
  
  You can render the file to DocBook 4.5 by setting the +:backend+ option to +:docbook+:
  
  [source]
  Asciidoctor.render_file 'sample.adoc', :in_place => true, :backend => :docbook
  
  The command will output to the file +sample.xml+ in the same directory.
  (If you're on Linux, you can view the file using yelp).
  