groupkill.go

package main

import (
	"log"
	"os"
	"os/exec"
	"syscall"
	"time"
)

func main() {
	path := os.Getenv("PATH")
	os.Setenv("PATH", path+":.")

	// start sub-command as a group leader
	cmd := exec.Command("parent.sh")
	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
	if err := cmd.Start(); err != nil {
		log.Fatal("Failed to Start(): " + err.Error())
	}

	// sleep 5 second
	<-time.After(3 * time.Second)
	displayPS()

	// kill sub-command
	pgid, err := syscall.Getpgid(cmd.Process.Pid)
	if err == nil {
		if err := syscall.Kill(-pgid, syscall.SIGKILL); err != nil {
			log.Fatal("Failed to Kill(): " + err.Error())
		}
	}

	time.Sleep(2 * time.Second)
	displayPS()

	if err := cmd.Wait(); err != nil {
		log.Fatal(err)
	}
}

func displayPS() {
	cmd := exec.Command("ps")
	cmd.Stdout = os.Stdout
	if err := cmd.Run(); err != nil {
		log.Fatal("Failed to exec 'ps x': " + err.Error())
	}
}