package main
import (
"flag"
"fmt"
"io/ioutil"
"os"
"path/filepath"
)
func main() {
flag.Parse()
roots := flag.Args()
if len(roots) == 0 {
roots = []string{"."}
}
fileSizes := make(chan int64)
go func() {
for _, root := range roots {
walkDir(root, fileSizes)
}
close(fileSizes)
}()
var nfiles, nbytes int64
for size := range fileSizes {
nfiles++
nbytes += size
}
printDiskUsage(nfiles, nbytes)
}
func walkDir(dir string, fileSizes chan<- int64) {
for _, entry := range dirents(dir) {
if entry.IsDir() {
subdir := filepath.Join(dir, entry.Name())
walkDir(subdir, fileSizes)
} else {
fileSizes <- entry.Size()
}
}
}
func dirents(dir string) []os.FileInfo {
entries, err := ioutil.ReadDir(dir)
if err != nil {
fmt.Fprintf(os.Stderr, "du: %v\n", err)
return nil
}
return entries
}
func printDiskUsage(nfiles, nbytes int64) {
fmt.Printf("%d files %.1f GB\n", nfiles, float64(nbytes)/1e9)
}