Replace placeholders in text file with Go

replace.go

func ReplaceInTemplate(filepath string, origString string, replaceString string) error {
  input, err := ioutil.ReadFile(filepath)
	if err != nil {
		return err
	}

	output := bytes.Replace(input, []byte(origString), []byte(replaceString), -1)

	if err = ioutil.WriteFile(filepath, output, 0666); err != nil {
		return err
	}

	return nil
}