code: public function handle(): void
      {
          /* Help Guide Header */
          $help = " -----------------------------------------------------------------\n";
          $help .= " | Command Line Interface\n";
          $help .= " | See more in https://github.com/senhungwong/command-line-interface\n";
          $help .= " -------------------------------------------------------------------\n";
  
          /* Get All Commands */
          $commands = CommandEntry::getCommands();
  
          /* See Specific Function's Description */
          if ($command = $this->getArgument('function-name')) {
              $command = new $commands[$command];
              $help .= " - " . $command->getCommand() . ": ";
              $help .= $command->getDescription() . "\n";
          }
  
          /* List All Commands */
          else {
              foreach ($commands as $command) {
                  $command = new $command;
                  $help .= " - ";
                  $help .= $command->getCommand() . ": ";
                  $help .= $command->getDescription() . "\n";
              }
          }
  
          echo $help;
      }
docs: Help command handler
  
  @return void