# File lib/rubygems/gem_commands.rb, line 741
    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