anchor.diff:  
   See the files [file]_default-theme.yml_ and [file]_asciidoctor-theme.yml_ found in the [file]_data/themes_ directory for examples.
   
  -== Additional Scripts
  +== Optional Scripts
   
   {project-name} also provides a shell script that invokes GhostScript (+gs+) to optimize and compress the generated PDF with minimal impact on quality.
   You must have Ghostscript installed to use it.
  
positive.code:  $ ./bin/optimize-pdf example.pdf
  
  The command will generate the file [file]_example-optimized.pdf_ in the current directory.
  If a file is found with the extension +.pdfmarks+ and the same rootname as the input file, it is used to add metadata to the generated PDF document.
  This file is necessary to preserve the document metadata since Ghostscript will otherwise drop it.
  That's why Asciidoctor PDF always creates this file in addition to the PDF.
  
negative.code: 
  == Prerequisites
  
  All that's needed is Ruby 1.9.3 or better (2.1.2 recommended) and a few RubyGems, which we explain how to install in the next section.
  
  To check you have Ruby available, use the +ruby+ command to query the version installed:
  
  