anchor.diff:  ...
   public static void main(String[] args) {
       AnsiConsole.systemInstall(); // Jansi magic
  -    CommandLine.run(new WindowsJansiDemo(), args);
  +    CommandLine.run(new WindowsJansiDemo(), System.err, Ansi.ON, args);
       AnsiConsole.systemUninstall();
   }
   ----
  
positive.code: It is the responsibility of the application to check the field and show the usage help message:
  [source,java]
  ----
  Compress app = CommandLine.parse(new App(), args);
  if (app.helpRequested) {
     CommandLine.usage(new App(), System.err);
     return;
  
negative.code: === Best Practices for Command Line Interfaces
  
  When designing your command line application,
  the https://www.gnu.org/prep/standards/html_node/Command_002dLine-Interfaces.html#Command_002dLine-Interfaces[GNU recommendations] for command line interfaces and http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap12.html#tag_12_02[POSIX Utility Guidelines] may be useful.
  
  Generally, many applications use options for optional values and parameters for mandatory values.
  However, picocli lets you make options required if you want to, see <<Required Arguments>>.
  
  
  