连续读取exec.Cmd输出

Question

Guys I am trying pick new lines as they come from command output, but always I end up doing it synchronous way (I have to wait until script is finished). I tired to use fsnotify but it is working only with regular files, do you have any idea how it can be done ?

package main
import (
   "fmt"
   "os/exec"
   "bytes"
   "os"
)

func main() {
   cmd := exec.Command("scripts/long_script")
   output := new(bytes.Buffer)
   cmd.Stdout = output
   cmd.Stderr = output
   if err := cmd.Start(); err != nil{ // after Start program is continued and script is executing in background
     fmt.Printf("Failed to start " + err.Error())
     os.Exit(1)
   }
   fmt.Printf(" Before WAIT %s 
", output.String())  // script is writing but nothing can be read from output
   cmd.Wait()
   fmt.Printf(" After Wait %s 
", output.String())  // if we wait to finish execution, we can read all output
}

Answer 1

eventually I managed to do it with []bytes

stdout, err := cmd.StdoutPipe()
buff := make([]byte,10)
var n int
for err == nil {
    n,err = stdout.Read(buff)
    if n > 0{
        fmt.Printf("taken %d chars %s",n,string(buff[:n]))
    }
}
cmd.Wait()
if cmd.ProcessState.Success() {. // ProcessState is set after Wait
    fmt.Println("Script success")  
} else {
    fmt.Println("Script failed")
}