gistfile1.txt

package main

import (
    "bytes"
    "fmt"
    "io"
    "os"
)
    
func main() {
    stdout := os.Stdout
    r, w, _ := os.Pipe()
    
    os.Stdout = w
    defer func() { os.Stdout = stdout }()

    done := make(chan bool)

    var testOutput bytes.Buffer
        
    go func() { 
        io.Copy(&testOutput, r)
        done <- true
    }()
    
    fmt.Printf("Hello world")
    os.Stdout.Close()
    
    <-done
    os.Stdout = stdout

    fmt.Printf("RESULT: %s\n", testOutput.String())
}