Watch

// Watch looks at current directory, if there are files changing, it runs a command.

package main

import (

"flag"

"fmt"

"io/ioutil"

"os/exec"

"strings"

"time"

)

var CheckInterval = flag.Int64("t", 2, "Interval in seconds between checks.")

func Usage() {

fmt.Println("Watch [-t <interval>] <command>")

}

func main() {

flag.Parse()

now := time.Now()

fmt.Println("From now on,", flag.Args(), "will be run on file change.")

willRun := false

for {

willRun = false

files, _ := ioutil.ReadDir(".")

for _, f := range files {

willRun = now.Before(f.ModTime())

if willRun {

fmt.Println("\nFile changed: ", f.Name())

break

}

}

if willRun {

fmt.Println("Running: ", flag.Args())

out, _ := exec.Command("/bin/bash", "-c", strings.Join(flag.Args(), " ")).CombinedOutput()

fmt.Println(string(out))

} else {

fmt.Print(".")

}

now = time.Now()

time.Sleep(time.Duration(*CheckInterval) * time.Second)

}

}