package main

import (
	"fmt"
	"os"
)

var tmpFile = "./tmp.txt"

func tmpPrint() {
	fmt.Println("output")
}

func main() {
	old := os.Stdout // keep backup of the real stdout
	w, err := os.OpenFile(tmpFile, os.O_CREATE|os.O_WRONLY, 0644)
	if err != nil {
		fmt.Println(err)
		return
	}
	defer w.Close()
	os.Stdout = w

	tmpPrint()

	//outC := make(chan string)
	// copy the output in a separate goroutine so printing can't block indefinitely
	//go func() {
	//	var buf bytes.Buffer
	//	io.Copy(&buf, r)
	//	outC <- buf.String()
	//}()

	// back to normal state
	//w.Close()
	os.Stdout = old // restoring the real stdout
	//out := <-outC

	// reading our temp stdout
	fmt.Println("previous output:")
	//fmt.Print(out)
}