code: func unescapeFilepath(path string) (string, error) {
  	buf := make([]byte, 0, len(path))
  	llen := len(path)
  	for i := 0; i < llen; {
  		if path[i] == '\\' {
  			if llen < i+4 {
  				return "", fmt.Errorf("Invalid octal code: too short")
  			}
  			octalCode := path[(i + 1):(i + 4)]
  			val, err := strconv.ParseUint(octalCode, 8, 8)
  			if err != nil {
  				return "", fmt.Errorf("Invalid octal code: %v", err)
  			}
  			buf = append(buf, byte(val))
  			i += 4
  		} else {
  			buf = append(buf, path[i])
  			i++
  		}
  	}
  	return string(buf), nil
  }
docs: /*
   * from zfs diff`s escape function:
   *
   * Prints a file name out a character at a time.  If the character is
   * not in the range of what we consider "printable" ASCII, display it
   * as an escaped 3-digit octal value.  ASCII values less than a space
   * are all control characters and we declare the upper end as the
   * DELete character.  This also is the last 7-bit ASCII character.
   * We choose to treat all 8-bit ASCII as not printable for this
   * application.
   */