get the disk usage of a directory.

diskusage.go

package main

import (
	"fmt"
	"os"
	"path/filepath"
)

func main() {
	path, _ := os.Getwd()
	if len(os.Args) == 2 {
		path = os.Args[1]
	}

	fmt.Println("Scanning", path)
	reportUsage(path)
}

func reportUsage(path string) {
	f, _ := os.Open(path)
	files, _ := f.Readdir(-1)
	f.Close()
	result := make(chan sizeInfo)

	for _, file := range files {
		go dirSize(filepath.Join(path, file.Name()), result)
	}

	var total int64
	results := 0
	for info := range result {
		total += info.size
		fmt.Printf("%s:\t%d\n", info.name, info.size)
		results++
		if results == len(files) {
			break
		}
	}

	fmt.Printf("\nTotal:\t\t%d\n", total)
}

type sizeInfo struct {
	name string
	size int64
}

func dirSize(path string, result chan sizeInfo) {
	var size int64

	filepath.Walk(path, func(_ string, file os.FileInfo, err error) error {
		if err == nil {
			size += file.Size()
		}
		return nil
	})

	result <- sizeInfo{filepath.Base(path), size}
}