unzip (missing functionality of windows)

unzip.go

package main

import (
	"archive/zip"
	"errors"
	"fmt"
	"io"
	"log"
	"os"
	"path/filepath"
	"strings"
)

func main() {
	if len(os.Args) <= 1 {
		fmt.Println("usage: unzip file.zip [file2.zip, ...]")
		os.Exit(78)
	}
	for _, arg := range os.Args[1:] {
		err := unzip(arg)
		if err != nil {
			log.Fatal(err)
		}
	}
}

func unzip(archive string) error {
	reader, err := zip.OpenReader(archive)
	if err != nil {
		return err
	}
	defer reader.Close()

	target := filepath.Base(archive)
	if !strings.HasSuffix(target, ".zip") || len(target) <= 4 {
		return errors.New("not a zip fileNAME")
	}
	target = target[:len(target)-4]

	if err := os.MkdirAll(target, 0755); err != nil {
		return err
	}

	for _, file := range reader.File {
		path := filepath.Join(target, file.Name)
		if file.FileInfo().IsDir() {
			os.MkdirAll(path, file.Mode())
			continue
		}

		fileReader, err := file.Open()
		if err != nil {
			return err
		}
		defer fileReader.Close()

		targetFile, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, file.Mode())
		if err != nil {
			return err
		}
		defer targetFile.Close()

		if _, err := io.Copy(targetFile, fileReader); err != nil {
			return err
		}
	}

	return nil
}