golang执行命令操作 exec.Command

cmd := exec.Command("cmd")
 in := bytes.NewBuffer(nil)
 cmd.Stdin = in//绑定输入
 var out bytes.Buffer
 cmd.Stdout = &out //绑定输出
 go func() {
 in.WriteString("node E:/design/test.js\n")//写入你的命令，可以有多行，"\n"表示回车
 }()
 err = cmd.Start()
 if err != nil {
 log.Fatal(err)
 }
 log.Println(cmd.Args)
 err = cmd.Wait()
 if err != nil {
 log.Printf("Command finished with error: %v", err)
 }
 fmt.Println(out.String())

func main() {
  timeout := 5
  ctx, cancel := context.WithTimeout(context.Background(), time.Duration(timeout+5)*time.Second)
  defer cancel()
 
  cmdarray := []string{"-c", fmt.Sprintf("%s %s", "sleep", "10")}
  cmd := exec.CommandContext(ctx, "bash", cmdarray...)
  out, err := cmd.CombinedOutput()
 
  //if ctx.Err() == context.DeadlineExceeded {}
  fmt.Printf("ctx.Err : [%v]\n", ctx.Err())
  fmt.Printf("error  : [%v]\n", err)
  fmt.Printf("out   : [%s]\n", string(out))
}

ctx.Err : [context deadline exceeded]
error  : [signal: killed]
out   : []

ctx.Err : [<nil>]
error  : [exit status 1]
out   : [usage: sleep seconds
]