diff --git a/main.go b/main.go
index e98d4cf..0b4cb0f 100644
--- a/main.go
+++ b/main.go
@@ -2,15 +2,19 @@ package main
 
 import (
 	"flag"
+	"fmt"
 	"log"
+	"os"
 
 	_ "github.com/codingsince1985/checksum"
 )
 
 func main() {
-	var source_dir = flag.String("source_dir", "./", "Path to image folder (/srv/fwuploads-tmp/)")
-	var target_dir = flag.String("target_dir", "./", "Path to image folder in public (/srv/fwuploads/troisdorf)")
-	var branch = flag.String("branch", "", "Branch to work with")
+	var source_dir = flag.String("s", "", "Path to image folder (/srv/fwuploads-tmp/)")
+	var target_dir = flag.String("t", "", "Path to image folder in public (/srv/fwuploads/troisdorf)")
+	var branch = flag.String("b", "", "Branch to work with")
+	var dryrun = flag.Bool("d", false, "Dryrun, just show changes on filesystem")
+
 	flag.Parse()
 	sdir := *source_dir
 	tdir := *target_dir
@@ -19,10 +23,52 @@ func main() {
 	var source_dir_branch string = sdir + br + "/"
 	var target_dir_branch string = tdir + br + "/"
 
-	//generate manifest file for branch
-	err := generate_manifest(source_dir_branch)
-	if err != nil {
-		log.Println("Error generating Manifest file: ", err)
+	if is_firmware_folder(source_dir_branch) {
+		//generate manifest file for branch
+		if !(*dryrun) {
+			err := generate_manifest(source_dir_branch)
+			if err != nil {
+				log.Println("Error generating Manifest file: ", err)
+			}
+		}
+		release_branch(*branch, source_dir_branch, target_dir_branch, *dryrun)
+	}
+}
+
+func is_firmware_folder(s string) bool {
+
+	// check files in source_folder
+	files, err := os.ReadDir(s)
+	if err != nil {
+		fmt.Println("Fehler beim Lesen des Verzeichnisses:", err)
+		return false
+	}
+
+	sysupgradeCount := 0
+	factoryCount := 0
+	otherCount := 0
+
+	// look for folders
+	for _, file := range files {
+		if file.IsDir() {
+			// check name
+			switch file.Name() {
+			case "sysupgrade":
+				sysupgradeCount++
+			case "factory":
+				factoryCount++
+			case "other":
+				otherCount++
+			}
+		}
+	}
+
+	// if there only the 3 folders then continue
+	if sysupgradeCount == 1 && factoryCount == 1 && otherCount == 1 {
+		log.Println("this looks like a gluon folder! Go on!")
+		return true
+	} else {
+		log.Println("the source folder does not look like a gluon firmware output.")
+		return false
 	}
-	release_branch(*branch, source_dir_branch, target_dir_branch)
 }
diff --git a/manifest.go b/manifest.go
index d18032c..8a9a72c 100644
--- a/manifest.go
+++ b/manifest.go
@@ -39,7 +39,7 @@ func split_filenames(files []fs.FileInfo, dir string) []Files {
 		current_name := files[i].Name()
 		split := strings.Split(current_name, "-")
 		if split[0] != "gluon" {
-			fmt.Println("skipping ", current_name)
+			log.Println("skipping ", current_name)
 			continue
 		}
 		split_name := len(split) - 1
diff --git a/release.go b/release.go
index 6e86729..3e1704b 100644
--- a/release.go
+++ b/release.go
@@ -1,12 +1,11 @@
 package main
 
 import (
-	"fmt"
 	"log"
 	"os"
 )
 
-func release_branch(branch string, source_dir string, target_dir string) {
+func release_branch(branch string, source_dir string, target_dir string, dryrun bool) {
 	checkOldFolder, _ := os.ReadDir(source_dir)
 	checkNewFolder, _ := os.ReadDir(target_dir)
 	var newImages bool = false
@@ -17,19 +16,26 @@ func release_branch(branch string, source_dir string, target_dir string) {
 	if newImages {
 		// delete old firmware files in public folder
 		for _, file := range checkNewFolder {
-			err := os.Remove(target_dir + file.Name())
-			if err != nil {
-				log.Println("error deleting file: ", err)
+			if !(dryrun) {
+				err := os.RemoveAll(target_dir + file.Name())
+				if err != nil {
+					log.Println("error deleting file: ", err)
+				} else {
+					log.Println("removed file: ", file.Name())
+				}
 			} else {
-				log.Println("removed file: ", file.Name())
+				log.Println("DRYRUN: delete folder :", file.Name())
 			}
 		}
 
 		//move new files to folder
 		for _, file := range checkOldFolder {
-			os.Rename(source_dir+file.Name(), target_dir+file.Name())
-			fmt.Println("moved file: ", file.Name())
+			if !(dryrun) {
+				os.Rename(source_dir+file.Name(), target_dir+file.Name())
+				log.Println("moved file: ", file.Name())
+			} else {
+				log.Println("DRYRUN: move folder: ", file.Name())
+			}
 		}
-
 	}
 }