Redirect stdin when using exec

main.go

package main

import (
	"bytes"
	"context"
	"fmt"
	"os/exec"
	"sync"
	"time"
)

const echoScript = `while read line
do
   echo $line
done < /dev/stdin
`

func main() {

	var wg sync.WaitGroup

	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
	defer cancel()

	var stdin bytes.Buffer
	var stdout bytes.Buffer

	cmd := exec.CommandContext(ctx, "bash", "-c", echoScript)
	cmd.Stdin = &stdin
	cmd.Stdout = &stdout

	wg.Add(1)
	go func() {
		defer wg.Done()
		cmd.Run()
	}()

	stdin.WriteString("Hello-World\n")
	stdin.WriteString("This is a new line\n")

	wg.Wait()

	fmt.Println("Stdout:")
	fmt.Println(stdout.String())

}