    # File lib/chef/knife/role_show.rb, line 37
          def run
            @role_name = @name_args[0]

            if @role_name.nil?
              show_usage
              ui.fatal("You must specify a role name")
              exit 1
            end

            role = Chef::Role.load(@role_name)
            output(format_for_display(config[:environment] ? role.environment(config[:environment]) : role))
          end