Go program to pop up an image every 4 hours; as a remainder

motivier.go

package main

import (
	"io/ioutil"
	"log"
	"math/rand"
	"os/exec"
	"time"
)

const (
	image_command    = "imv"
	images_directory = "/home/ghd/me/pic/mot/"
)

func main() {
	files, err := ioutil.ReadDir(images_directory)
	if err != nil {
		log.Fatalf("Couldn't reach images directory %s: %s", images_directory, err)
	}
	rand.Seed(time.Now().UnixNano())
	rand.Shuffle(len(files), func(i, j int) { files[i], files[j] = files[j], files[i] })
	tk := time.NewTicker(3 * time.Hour)
	for i := 0; true; <-tk.C {
		f := files[i%len(files)]
		exec.Command(image_command, "-f", images_directory+f.Name()).Output()
		i++
	}
}