package main

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

func main() {
	fi, err := os.Lstat(".")
	if err != nil {
		log.Fatal(err)
	}
	last_mod := fi.ModTime()

	for ; ; {
		fi, err := os.Lstat("q8.pl")
		if err != nil {
			log.Fatal(err)
		}
		if last_mod != fi.ModTime() {
			fmt.Println(">> file updated.")
			cmd := exec.Command("perl", "q8.pl")
			out, err := cmd.Output()
			if err != nil {
				log.Fatal(err)
			}
			fmt.Printf("%s\n", out)
			last_mod = fi.ModTime()
		}
		time.Sleep(2000 * time.Millisecond)
	}
}