sleep less on Ctrl+C

main.go

package main

import (
	"fmt"
	"os"
	"os/signal"
	"time"
)

func main() {
	signals := make(chan os.Signal, 1)
	signal.Notify(signals, os.Interrupt)

	if len(os.Args) != 2 {
		fmt.Println("Specify time to sleep")
		os.Exit(1)
	}

	duration, err := time.ParseDuration(os.Args[1])
	if err != nil {
		fmt.Println(err)
		os.Exit(1)
	}

	end := time.Now().Add(duration)
	timer := time.NewTimer(duration)

	for {
		fmt.Printf("sleeping %s seconds\n", duration)

		select {
		case <-timer.C:
			fmt.Println("done")
			return

		case <-signals:
			if !timer.Stop() {
				<-timer.C
			}
			fmt.Println("half duration")
			duration = time.Until(end) / 2
			end = time.Now().Add(duration)
			timer = time.NewTimer(duration)
		}
	}
}