anchor.diff:  
   These two options were added because we defined the command with `@Command(mixinStandardHelpOptions = true /* ... */)`. Usage help and version information are so common for command line applications that picocli provides this shortcut. Internally this uses a mechanism called "mixins" and we will go into more detail later on how you can define your own mixins to define reusable elements. But first, let's see what these options actually do, starting with the `--version` option.
   
  +.Testing the version option
   ----
   $ java picocli.example.CheckSum --version
   checksum 3.0
   ----
   The version information shown is what was specified in the command annotation: `@Command(version = "checksum 3.0" /* ... */)`. We will show later that you can also get the version information from a JAR file's manifest or some other place. Next, the `--help` option:
   
  +.Testing the help option
   ----
   $ java picocli.example.CheckSum --help
   Usage: checksum [-hV] [-a=<algorithm>] <file>
  
positive.code: == Dynamic Version Information
  Remember that the `CheckSum` example showed version information from a static `@Command(version = "xxx")` attribute? Often you want to manage version information in a single place, and have picocli obtain this information dynamically at runtime. For example, an implementation may return version information obtained from the JAR manifest, a properties file or some other source.
  
  The `@Command` annotation supports a `versionProvider` attribute, where applications cay specify a `IVersionProvider` implementation class:
  
  [source,java]
  ----
  @Command(versionProvider = my.custom.VersionProvider.class)
  
negative.code: 
  You probably want to `chmod 755 checksum` to make the script executable. Try calling it on the command line with `./checksum --version` to see if the script works.
  
  Next, we generate the completion script for our `checksum` command. To do this, we invoke `picocli.AutoComplete`, and give it the name of the class and the name of the command:
  
  .Generating a completion script
  [source,bash]
  ----
  $ java -cp "checksum.jar:picocli-3.9.5.jar" picocli.AutoComplete -n checksum picocli.example.CheckSum
  ----
  
  This will generate a file called `checksum_completion` in the current directory.
  