# File lib/compass/exec/sub_command_ui.rb, line 30
    def perform!
      $command = args.shift
      command_class = Compass::Commands[$command]
      @options = if command_class.respond_to?("parse_#{$command}!")
        command_class.send("parse_#{$command}!", args)
      else
        command_class.parse!(args)
      end
      command_class.new(Dir.getwd, @options).execute
    rescue OptionParser::ParseError => e
      puts "Error: #{e.message}"
      puts command_class.usage
    end