def extract_files(src, file, flag, path)
      extract_data_error = File.join(@log_dir, "extract_data_error.log")

      cmd = "tar -x#{flag}Of #{src} #{file} >> #{path} 2>> " <<
        "#{extract_data_error}"
      system(cmd)
      if $?.exitstatus > 0
        raise "Data extraction error. " <<
          "See #{extract_data_error} for details."
      end
    end
def extract_files(src, file, flag, path)
      extract_data_error = File.join(@log_dir, "extract_data_error.log")

      cmd = "tar -x#{flag}Of #{src} #{file} >> #{path} 2>> " <<
        "#{extract_data_error}"
      system(cmd)
      if $?.exitstatus > 0
        raise "Data extraction error. " <<
          "See #{extract_data_error} for details."
      end
    end
Extracts and concatenates files from tarballs.