anchor.diff:  template with an ERB template, put a file named
   `block_paragraph.html.erb` in the template directory you pass to the
   `Document` constructor using the `template_dir` option.
  -
  -.Commandline
  -If you don't like all this Ruby code just to render AsciiDoc, there's a
  -commandline interface (cli) named `asciidoctor`. It should be available
  -on your PATH after installing the gem. The `asciidoctor` command is a
  -drop-in replacement for the `asciidoc` command from the AsciiDoc Python
  -distribution.
   
   For more usage examples, see the (massive) test suite.
   
  
positive.code: 
   asciidoctor --help
  
  , or in the man page. There is also an `asciidoctor-safe` command, which
  turns on safe mode, preventing access to files outside the parent
  directory of the source file. This is very similar to the safe mode
  of `asciidoc.py`.
  
  === Asciidoctor API
  
  To use Asciidoctor in your application, you first need to require the
  gem:
  
negative.code: == Usage
  
  Asciidoctor has both a command line interface (CLI) and an API. The
  CLI is a drop-in replacement for the `asciidoc.py` command from the
  python implementation. The API is intended for integration with other
  software projects and is suitable for server-side applications, such
  as Rails, Sinatra and GitHub.
  
  === Command line interface (CLI)
  
  After installing the `asciidoctor` gem, the `asciidoctor` commandline
  interface should be available on your PATH after installing the gem.
  To invoke it, simply execute:
  
   asciidoctor <asciidoc_file>
  
  