seek.go

package main

import (
	"fmt"
	"os"
	"time"
)

const logFile = "/tmp/file.txt"

func main() {
	stats, err := os.Stat(logFile)
	if err != nil {
		panic(err)
	}

	size := stats.Size()
	fmt.Printf("Openfile of size: %d\n", size)

	f, err := os.OpenFile(logFile, os.O_RDONLY, 0600)
	if err != nil {
		panic(err)
	}
	defer f.Close()
	seekTo := size - 100

	fmt.Printf("Start seeking to %d\n", seekTo)
	start := time.Now()
	f.Seek(seekTo, os.SEEK_SET)
	b := make([]byte, 1024)
	if _, err := f.Read(b); err != nil {
		panic(err)
	}
	end := time.Now()
	fmt.Println(b)

	fmt.Printf("Seek took: %s\n", end.Sub(start))
}