md5.go

package main

import (
	"bufio"
	"crypto/md5"
	"fmt"
	"os"
	"time"

	goCache "github.com/pmylund/go-cache"
)

func main() {
	fp, err := os.Open(os.Args[1])
	if err != nil {
		panic(err)
	}
	defer fp.Close()

	c := goCache.New(5*time.Minute, 30*time.Second)

	var key string
	scanner := bufio.NewScanner(fp)
	for scanner.Scan() {
		key = fmt.Sprintf("%x", md5.Sum(scanner.Bytes()))[0:12]
		value, found := c.Get(key)
		if found {
			fmt.Println(value, key, scanner.Text())
		} else {
			c.Set(fmt.Sprintf("%x", md5.Sum(scanner.Bytes()))[0:12], scanner.Text(), -1)
		}
	}
}