# File lib/rubygems/commands/build_command.rb, line 18
      def execute
        gemspec = get_one_gem_name
        if File.exist?(gemspec)
          specs = load_gemspecs(gemspec)
          specs.each do |spec|
            Gem::Builder.new(spec).build
          end
          return
        else
          alert_error "Gemspec file not found: #{gemspec}"
        end
      end