code: func existsForOldIpTables(table string, ruleSpec string) (bool, error) {
  	cmd := exec.Command("iptables", "-t", table, "-S")
  	var out bytes.Buffer
  	cmd.Stdout = &out
  	err := cmd.Run()
  	if err != nil {
  		return false, err
  	}
  	rules := out.String()
  	return strings.Contains(rules, ruleSpec), nil
  }
docs: // Checks if a rule specification exists for a table