Renames URL-encoded filenames like %FU%CK%IN%G0 to normal text.

fileurldec.go

package main

import (
  "flag"
	"fmt"
	"net/url"
	"os"
	"path/filepath"
)

func main() {
	flag.Parse()
	if flag.NArg() != 1 {
		fmt.Fprintln(os.Stderr, "usage: fileurldec path/to/directory")
		os.Exit(1)
	}

	rootPath := flag.Arg(0)
	paths := make([]string, 0)
	err := filepath.Walk(rootPath, func (path string, info os.FileInfo, err error) error {
		paths = append(paths, path)
		return nil
	})
	if err != nil {
		fmt.Fprintf(os.Stderr, "%s", err)
		os.Exit(1)
	}

	for _, path := range paths {
		fullPath, err := filepath.Abs(path)
		if err != nil {
			fmt.Fprintf(os.Stderr, "* ERROR: %s", err)
			continue
		}
		name := filepath.Base(fullPath)
		decodedName, err := url.QueryUnescape(name)
		if err != nil {
			fmt.Fprintf(os.Stderr, "* ERROR: %s", err)
			continue
		}
		newPath := filepath.Join(filepath.Dir(fullPath), decodedName)
		if newPath == fullPath {
			continue
		}
		// Rename!
		if err := os.Rename(fullPath, newPath); err != nil {
			fmt.Fprintf(os.Stderr, "%s", err)
			continue
		}
		fmt.Printf("Renamed %s\n", newPath)
	}
}