# File ../../auditor/lib/kasp_auditor/partial_auditor.rb, line 499
      def grep_for_domains_of_interest(file, domain_filename)
        # Use the parent.domain_list to grep for all the instances of the domains we're after.
        list = @parent.domain_list + @parent.hashed_domain_list
        grep_command = "#{Commands.grep} '"
        first = true
        list.each {|domain|
          if first
            first = false
            grep_command+="^#{domain}"
          else
            grep_command+="\\|^#{domain}"
          end
          break if grep_command.length > 50000
        }
        grep_command= (grep_command + "' #{file}  >> #{domain_filename}").untaint
        system(grep_command)
      end