code: func checkSCPStatus(r *bufio.Reader) error {
  	code, err := r.ReadByte()
  	if err != nil {
  		return err
  	}
  
  	if code != 0 {
  		// Treat any non-zero (really 1 and 2) as fatal errors
  		message, _, err := r.ReadLine()
  		if err != nil {
  			return fmt.Errorf("Error reading error message: %s", err)
  		}
  
  		return errors.New(string(message))
  	}
  
  	return nil
  }
docs: // checkSCPStatus checks that a prior command sent to SCP completed
  // successfully. If it did not complete successfully, an error will
  // be returned.