code: func IsTerminal(file *os.File) bool {
  	rv, err := C.isatty(C.int(file.Fd()))
  	if err != nil {
  		return false
  	}
  	if rv != 0 {
  		return true
  	}
  	return false
  }
docs: // May move to util/file? For now is here because it's the only
  // one used by colors.