code: func (ui *CommandlineUI) readString() string {
  	for {
  		fmt.Printf("> ")
  		text, err := ui.in.ReadString('\n')
  		if err != nil {
  			log.Crit("Failed to read user input", "err", err)
  		}
  		if text = strings.TrimSpace(text); text != "" {
  			return text
  		}
  	}
  }
docs: // readString reads a single line from stdin, trimming if from spaces, enforcing
  // non-emptyness.