b, err := ioutil.ReadAll(r)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Printf("%s", b)

	// Output:
	// Go is a general-purpose language designed with systems programming in mind.
}

func ExampleReadDir() {
	files, err := ioutil.ReadDir(".")
	if err != nil {
		log.Fatal(err)
	}

	for _, file := range files {
		fmt.Println(file.Name())
	}
}

func ExampleTempDir() {

	// Output:
	// gopher lives in /usr/gopher.
}

func ExampleUnsetenv() {
	os.Setenv("TMPDIR", "/my/tmp")
	defer os.Unsetenv("TMPDIR")
}

func ExampleReadDir() {
	files, err := os.ReadDir(".")
	if err != nil {
		log.Fatal(err)
	}

	for _, file := range files {
		fmt.Println(file.Name())
	}
}

func ExampleMkdirTemp() {