    # File lib/rubygems/commands/rdoc_command.rb, line 48
          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