code: func (r *cmdRun) done(err error) int {
  	if err != nil {
  		fmt.Fprintln(os.Stderr, err)
  		if err, ok := err.(*exitCode); ok {
  			return err.code
  		}
  		return ecOtherError
  	}
  	return 0
  }
docs: // done prints err to stderr if it is not nil and returns an exit code.