package main

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

func Start(args ...string) (pid int) {
	if binary, lookErr := exec.LookPath(args[0]); lookErr == nil {
		args[0] = binary
		var procAttr syscall.ProcAttr
		procAttr.Files = []uintptr{uintptr(syscall.Stdin),
			uintptr(syscall.Stdout), uintptr(syscall.Stderr)}
		p, execErr := syscall.ForkExec(args[0], args[1:], &procAttr)
		if execErr != nil {
			panic(execErr)
		}
		pid = p
	} else {
		panic(lookErr)
	}
	return
}

func Wait(pid int) {
	proc, err := os.FindProcess(pid)
	if err == nil {
		for {
			ps, err := proc.Wait()
			if ps.Exited() && err == nil {
				return
			}
		}
	}
	panic(err)
}

func main() {
	pid := Start("bash")
	Wait(pid)
}