scratchpad: repeat: run a command in a certain interval or as soon as it finishes

scratchpad/repeat/main.go

@@ -0,0 +1,46 @@
+package main
+
+import (
+	"log"
+	"os"
+	"os/exec"
+	"time"
+)
+
+var config struct {
+	duration time.Duration
+}
+
+func usage() {
+	log.Printf("usage: repeat repeatInterval command [args...]")
+}
+
+func main() {
+
+	args := os.Args
+
+	if len(args) < 3 {
+		usage()
+		os.Exit(1)
+	}
+	repeatInterval, err := time.ParseDuration(args[1])
+	if err != nil {
+		log.Printf("cannot parse interval: %s", err)
+		usage()
+		os.Exit(1)
+	}
+
+	var lastStart time.Time
+
+	for {
+		cmd := exec.Command(args[2], args[3:]...)
+		cmd.Stdout = os.Stdout
+		cmd.Stderr = os.Stderr
+		lastStart = time.Now()
+		if err := cmd.Run(); err != nil {
+			panic(err)
+		}
+		time.Sleep(lastStart.Add(repeatInterval).Sub(time.Now()))
+	}
+
+}

scratchpad/repeat/sleepx.sh

@@ -0,0 +1,6 @@
+#!/bin/sh
+echo -n ' start '
+date
+sleep $1
+echo -n 'done '
+date