Go program to untar multiple gzipped tarballs listed on the command line

untar.go

package main

import (
	"archive/tar"
	"compress/gzip"
	"fmt"
	"io"
	"os"
	"path/filepath"
)

// https://gist.github.com/sdomino/635a5ed4f32c93aad131#file-untargz-go
func Untar(dst string, r io.Reader) error {
	gzr, err := gzip.NewReader(r)
	if err != nil {
		return err
	}
	defer gzr.Close()

	tr := tar.NewReader(gzr)

	for {
		header, err := tr.Next()

		switch {

		// if no more files are found return
		case err == io.EOF:
			return nil

		// return any other error
		case err != nil:
			return err

		// if the header is nil, just skip it (not sure how this happens)
		case header == nil:
			continue
		}

		// the target location where the dir/file should be created
		target := filepath.Join(dst, header.Name)

		// the following switch could also be done using fi.Mode(), not sure if there
		// a benefit of using one vs. the other.
		// fi := header.FileInfo()

		// check the file type
		switch header.Typeflag {

		// if its a dir and it doesn't exist create it
		case tar.TypeDir:
			if _, err := os.Stat(target); err != nil {
				if err := os.MkdirAll(target, 0755); err != nil {
					return err
				}
			}

		// if it's a file create it
		case tar.TypeReg:
			f, err := os.OpenFile(target, os.O_CREATE|os.O_RDWR, os.FileMode(header.Mode))
			if err != nil {
				return err
			}

			// copy over contents
			_, err = io.Copy(f, tr)
			f.Close()
			if err != nil {
				return err
			}
		}
	}
}

func abort(err error) {
	fmt.Fprintf(os.Stderr, "Error: %s\n", err)
	os.Exit(1)
}

func main() {
	if len(os.Args) < 2 {
		abort(fmt.Errorf("insufficient arguments"))
	} else {
		destination, _ := os.Getwd()
		for _, tarfile := range os.Args[1:] {
			tar, err := os.Open(tarfile)
			if err != nil {
				abort(err)
			}
			err = Untar(destination, tar)
			tar.Close()
			if err != nil {
				abort(err)
			}
			fmt.Println(tarfile)
		}
	}
}