code: func CopyFile(newFile, oldFile string) error {
  	input, err := ioutil.ReadFile(oldFile)
  	if err != nil {
  		return err
  	}
  	err = ioutil.WriteFile(newFile, []byte(input), 0644)
  	if err != nil {
  		return err
  	}
  	return nil
  }
docs: // CopyFile()