code: func GoFmt(files ...string) *exec.Cmd {
  	if len(files) == 0 {
  		files = []string{"."}
  	}
  	c := "gofmt"
  	_, err := exec.LookPath("goimports")
  	if err == nil {
  		c = "goimports"
  	}
  	_, err = exec.LookPath("gofmt")
  	if err != nil {
  		return exec.Command("echo", "could not find gofmt or goimports")
  	}
  	args := []string{"-w"}
  	args = append(args, files...)
  	return exec.Command(c, args...)
  }
docs: // GoFmt is command that will use `goimports` if available,
  // or fail back to `gofmt` otherwise.