anchor.diff:  
    $ bundle
   
  -=== Yum (Fedora 18 or greater)
  -
  -Open a terminal and type:
  +To upgrade the gem, set the new version in the Gemfile and run `bundle` again.
  +Using `bundle update` is not recommended as it will also update other gems, which may not be the desired result.
  +
  +=== (c) Linux package managers
  +
  +==== Yum (Fedora 18 or greater)
  +
  +To install the gem on Fedora 18 or greater using yum, open a terminal and type:
   
    $ sudo yum install -y rubygem-asciidoctor
   
  -=== apt-get (Debian Sid, Ubuntu Saucy or greater)
  -
  -Open a terminal and type:
  +To upgrade the gem, use:
  +
  + $ sudo yum update -y rubygem-asciidoctor
  +
  +TIP: Your Fedora system may be configured to automatically update packages, in which case no action is required by you to update the gem.
  +
  +==== apt-get (Debian Sid, Ubuntu Saucy or greater)
  +
  +To install the gem on Debian or Ubuntu, open a terminal and type:
   
    $ sudo apt-get install -y asciidoctor
  +
  +To upgrade the gem, use:
  +
  + $ sudo apt-get upgrade -y asciidoctor
  +
  +TIP: Your Debian or Ubuntu system may be configured to automatically update packages, in which case no action is required by you to update the gem.
   
   === Other installation options
   
   * {install-doc-uri}[Installing the Asciidoctor toolchain]
   * {install-osx-doc-uri}[Installing Asciidoctor on Mac OS X]
   
  -=== Upgrading
  -
  -If you have an earlier version of Asciidoctor installed, you can update it using:
  -
  - $ gem update asciidoctor
  -
  -[TIP]
  ---
  -If you install a new version of the gem using `gem install` instead of `gem update`, then you'll have multiple versions installed.
  -If you wish to remove older versions, use the following `gem` command:
  -
  - $ gem cleanup asciidoctor
  ---
  -
  -On Fedora, you can update it using:
  -
  - $ sudo yum update -y rubygem-asciidoctor
  -
  -TIP: Your Fedora system may be configured to automatically update packages, in which case no further action is required by you.
  -Refer to the https://docs.fedoraproject.org[Fedora docs] if you are unsure.
  -
  -On Debian or Ubuntu, you can update it using:
  -
  - $ sudo apt-get upgrade -y asciidoctor
  -
   == Usage
   
   If the Asciidoctor gem installed successfully, the `asciidoctor` command line interface (CLI) will be available on your PATH.
  
positive.code: [source]
  ----
  content = '_Zen_ in the art of writing http://asciidoctor.org[AsciiDoc].'
  document = Asciidoctor.load content, header_footer: true, safe: :safe
  puts document.doctitle
  html = document.convert
  ----
  
negative.code: * Opal (JavaScript)
  
  We welcome your help testing Asciidoctor on other platforms as well.
  Refer to <<{idprefix}contributing,Contributing>> to learn how to get involved.
  
  == Installation
  
  Asciidoctor can be installed using (a) the `gem install` command, (b) Bundler or (c) package managers for popular Linux distributions.
  
  TIP: The benefit of using a Linux package manager to install the gem is that it handles installing Ruby and RubyGems if they're not already installed on your machine.
  The drawback is that package may not be available immediately after the release of the RubyGem.
  If you need the latest version, you can always fallback to using the `gem` command.
  
  === (a) gem install
  
  Open a terminal and type: (without the leading `$`)
  
   $ gem install asciidoctor
  
  If you want to install a pre-release version (e.g., a release candidate), use:
  
   $ gem install asciidoctor --pre
  
  .Upgrading your installation
  [TIP]
  ====
  If you have an earlier version of Asciidoctor installed, you can update it using:
  
   $ gem upgrade asciidoctor
  
  If you install a new version of the gem using `gem install` instead of gem update, you'll have multiple versions installed.
  If that's the case, use the following gem command to remove the old versions:
  
   $ gem cleanup asciidoctor
  ====
  
  === (b) Bundler
  
  . Create a Gemfile in the root folder of your project (or the current directory)
  . Add the `asciidoctor` gem to your Gemfile as follows:
  