Output file size and check if a duplicate exists for all files in a specific directory

recursiveFileInfo.go

package main

import (
  "os"
  "fmt"
  "log"
  "crypto/sha512"
  "io/ioutil"
  "path/filepath"
)

var files = make(map[[sha512.Size]byte]string)

func printFile(path string, info os.FileInfo, err error) error {
  if err != nil {
    log.Print(err)
    return nil
  }
  du(path, info)
  checkDuplicate(path, info)
  fmt.Println("")
  return nil
}

func du(path string, info os.FileInfo) {
    size := info.Size()
    if !info.IsDir() {
        fmt.Printf("%s: %d Bytes\n", path, size)
    }
}

func checkDuplicate(path string, info os.FileInfo) error {
    if info.IsDir() {
        return nil
    }

    data, err := ioutil.ReadFile(path)
    if err != nil {
        log.Print(err)
        return nil
    }
    digest := sha512.Sum512(data)
    if v, ok := files[digest]; ok {
        fmt.Printf("%q is a duplicate of %q\n", path, v)
    } else {
        files[digest] = path
    }

    return nil
}

func main() {
  log.SetFlags(log.Lshortfile)
  dir := os.Args[1]
  err := filepath.Walk(dir, printFile)
  if err != nil {
    log.Fatal(err)
  }
}