# File lib/rubygems/gem_commands.rb, line 1243
    def execute
      if options[:all]
        specs = Gem::SourceIndex.from_installed_gems.collect { |name, spec|
          spec
        }
      else
        gem_name = get_one_gem_name
        specs = Gem::SourceIndex.from_installed_gems.search(
          gem_name, options[:version])
      end

      if specs.empty?
        fail "Failed to find gem #{gem_name} to generate RDoc for #{options[:version]}"
      end
      if options[:include_ri]
        specs.each do |spec|
          Gem::DocManager.new(spec).generate_ri
        end
      end
      if options[:include_rdoc]
        specs.each do |spec|
          Gem::DocManager.new(spec).generate_rdoc
        end
      end

      true
    end