code: func (c *LogCmd) Run() error {
  	if c.Cmd.Stdout == nil && c.Cmd.Stderr == nil {
  		_, err := c.Output()
  		return err
  	}
  
  	st := time.Now()
  	err := c.Cmd.Run()
  	c.log(st, err, nil)
  	return err
  }
docs: // Run overrides exec.Cmd.Run to record the result.
  // If both Cmd.Stdout and Cmd.Stderr are nil, this calls Output
  // instead to log stderr.