    # File lib/rubygems/commands/dependency_command.rb, line 45
      def execute
        options[:args] << '' if options[:args].empty?
        specs = {}

        source_indexes = Hash.new do |h, source_uri|
          h[source_uri] = Gem::SourceIndex.new
        end

        pattern = if options[:args].length == 1 and
                     options[:args].first =~ /\A\/(.*)\/(i)?\z/m then
                    flags = $2 ? Regexp::IGNORECASE : nil
                    Regexp.new $1, flags
                  else
                    /\A#{Regexp.union(*options[:args])}/
                  end

        dependency = Gem::Dependency.new pattern, options[:version]

        if options[:reverse_dependencies] and remote? and not local? then
          alert_error 'Only reverse dependencies for local gems are supported.'
          terminate_interaction 1
        end

        if local? then
          Gem.source_index.search(dependency).each do |spec|
            source_indexes[:local].add_spec spec
          end
        end

        if remote? and not options[:reverse_dependencies] then
          fetcher = Gem::SpecFetcher.fetcher

          begin
            fetcher.find_matching(dependency).each do |spec_tuple, source_uri|
              spec = fetcher.fetch_spec spec_tuple, URI.parse(source_uri)

              source_indexes[source_uri].add_spec spec
            end
          rescue Gem::RemoteFetcher::FetchError => e
            raise unless fetcher.warn_legacy e do
              require 'rubygems/source_info_cache'

              specs = Gem::SourceInfoCache.search_with_source dependency, false

              specs.each do |spec, source_uri|
                source_indexes[source_uri].add_spec spec
              end
            end
          end
        end

        if source_indexes.empty? then
          patterns = options[:args].join ','
          say "No gems found matching #{patterns} (#{options[:version]})" if
            Gem.configuration.verbose

          terminate_interaction 1
        end

        specs = {}

        source_indexes.values.each do |source_index|
          source_index.gems.each do |name, spec|
            specs[spec.full_name] = [source_index, spec]
          end
        end

        reverse = Hash.new { |h, k| h[k] = [] }

        if options[:reverse_dependencies] then
          specs.values.each do |_, spec|
            reverse[spec.full_name] = find_reverse_dependencies spec
          end
        end

        if options[:pipe_format] then
          specs.values.sort_by { |_, spec| spec }.each do |_, spec|
            unless spec.dependencies.empty?
              spec.dependencies.each do |dep|
                say "#{dep.name} --version '#{dep.version_requirements}'"
              end
            end
          end
        else
          response = ''

          specs.values.sort_by { |_, spec| spec }.each do |_, spec|
            response << print_dependencies(spec)
            unless reverse[spec.full_name].empty? then
              response << "  Used by\n"
              reverse[spec.full_name].each do |sp, dep|
                response << "    #{sp} (#{dep})\n"
              end
            end
            response << "\n"
          end

          say response
        end
      end