diff --git a/archiver.go b/archiver.go
index 096eb036..5cfdc78e 100644
--- a/archiver.go
+++ b/archiver.go
@@ -192,21 +192,15 @@ func Archive(sources []string, destination string) error {
 }
 
 // Unarchive unarchives the given archive file into the destination folder.
-// The archive format is selected implicitly based on the file's header.
+// The archive format is selected implicitly.
 func Unarchive(source, destination string) error {
-	f, err := os.Open(source)
+	uaIface, err := ByExtension(source)
 	if err != nil {
 		return err
 	}
-	uaIface, err := ByHeader(f)
-	if err != nil {
-		f.Close()
-		return err
-	}
-	f.Close()
 	u, ok := uaIface.(Unarchiver)
 	if !ok {
-		return fmt.Errorf("format specified by destination filename is not an archive format: %s (%T)", destination, uaIface)
+		return fmt.Errorf("format specified by source filename is not an archive format: %s (%T)", source, uaIface)
 	}
 	return u.Unarchive(source, destination)
 }
diff --git a/cmd/arc/main.go b/cmd/arc/main.go
index b0ccc797..00f44270 100644
--- a/cmd/arc/main.go
+++ b/cmd/arc/main.go
@@ -51,8 +51,6 @@ func main() {
 		fatal(err)
 	}
 
-	fmt.Printf("VALUE: %#v\n", iface)
-
 	// run the desired command
 	switch subcommand {
 	case "archive":
@@ -63,11 +61,11 @@ func main() {
 		err = a.Archive(flag.Args()[2:], flag.Arg(1))
 
 	case "unarchive":
-		a, ok := iface.(archiver.Unarchiver)
+		u, ok := iface.(archiver.Unarchiver)
 		if !ok {
 			fatalf("the unarchive command does not support the %s format", iface)
 		}
-		err = a.Unarchive(flag.Arg(1), flag.Arg(2))
+		err = u.Unarchive(flag.Arg(1), flag.Arg(2))
 
 	case "extract":
 		e, ok := iface.(archiver.Extractor)
@@ -124,7 +122,7 @@ func main() {
 			return nil
 		})
 
-		fmt.Printf("total %d", count)
+		fmt.Printf("total %d\n", count)
 
 	case "compress":
 		c, ok := iface.(archiver.Compressor)