def run!
      trace = @always_trace || false
      require_program :version, :description
      trap('INT') { abort program(:int_message) } if program(:int_message)
      trap('INT') { program(:int_block).call } if program(:int_block)
      global_option('-h', '--help', 'Display help documentation') do
        args = @args - %w(-h --help)
        command(:help).run(*args)
        return
      end
      global_option('-v', '--version', 'Display version information') do
        say version
        return
      end
      global_option('-t', '--trace', 'Display backtrace when an error occurs') { trace = true } unless @never_trace || @always_trace
      parse_global_options
      remove_global_options options, @args
      if trace
        run_active_command
      else
        begin
          run_active_command
        rescue InvalidCommandError => e
          abort "#{e}. Use --help for more information"
        rescue \
          OptionParser::InvalidOption,
          OptionParser::InvalidArgument,
          OptionParser::MissingArgument => e
          abort e.to_s
        rescue StandardError => e
          if @never_trace
            abort "error: #{e}."
          else
            abort "error: #{e}. Use --trace to view backtrace"
          end
        end
      end
    end
#
Run command parsing and execution process.