anchor.diff:  
   [source,bash]
   ----
  -curl 'http://localhost:8983/solr/gettingstarted/update/extract?literal.id=doc1&uprefix=ignored_&commit=true' -F "myfile=@example/exampledocs/solr-word.pdf"
  +curl 'http://localhost:8983/solr/gettingstarted/update/extract?literal.id=doc1&commit=true' -F "myfile=@example/exampledocs/solr-word.pdf"
   ----
   
   The URL above calls the `ExtractingRequestHandler`, uploads the file `solr-word.pdf`, and assigns it the unique ID `doc1`. Here's a closer look at the components of this command:
  
positive.code: 
  * The `-F` flag instructs curl to POST data using the Content-Type `multipart/form-data` and supports the uploading of binary files. The `@` symbol instructs curl to upload the attached file.
  
  * The argument `myfile=@example/exampledocs/solr-word.pdf` uploads the sample file.Note this includes the path, so if you upload a different file, always be sure to include either the relative or absolute path to the file.
  
  You can also use `bin/post` to do the same thing:
  
  
negative.code: The `uprefix` parameter only applies to fields that are _undefined_, so these won't be prefixed if the document is reindexed later.
  However, you would see the new `last_modified_dt` field.
  
  The easiest way to try out the `uprefix` parameter is to start over with a fresh collection.
  ====
  
  == ExtractingRequestHandler Parameters and Configuration
  