gistfile1.rb

//https://github.com/fluent/fluentd/blob/master/lib/fluent/command/fluentd.rb 
//line 81-91

op.on('-v', '--verbose', "increase verbose level (-v: debug, -vv: trace)", TrueClass) {|b|
  if b
    opts[:log_level] = [opts[:log_level] - 1, Fluent::Log::LEVEL_TRACE].max
  end
}

op.on('-q', '--quiet', "decrease verbose level (-q: warn, -qq: error)", TrueClass) {|b|
  if b
    opts[:log_level] = [opts[:log_level] + 1, Fluent::Log::LEVEL_ERROR].min
  end
}