return errors and handle os.Exit in cmd file

internal/ripsort.go

@@ -10,12 +10,12 @@ import (
 	"git.kapelle.org/niklas/ripsort/internal/metadata"
 )
 
-func Scan(filePath string) {
+func Scan(filePath string) error {
 	info, err := metadata.ReadAudioTags(filePath)
 
 	if err != nil {
 		slog.Error("Reading metadata", "file", filePath, "err", err)
-		os.Exit(1)
+		return err
 	}
 
 	fmt.Printf("Title:        %s\n", info.Title)
@@ -27,26 +27,28 @@ func Scan(filePath string) {
 
 	sortPath := pathForFile(filePath, *info)
 	fmt.Printf("Sort path:    %s\n", sortPath)
+
+	return nil
 }
 
-func Sort(dst, path string) {
+func Sort(dst, path string) error {
 	info, err := os.Stat(path)
 	if err != nil {
 		slog.Error("Failed to stat path", "file", path, "err", err)
-		os.Exit(1)
+		return err
 	}
 
 	// Handle single file
 	if !info.IsDir() {
 		if !fileSupported(path) {
 			slog.Error("Unsupported file format", "file", path)
-			os.Exit(1)
+			return err
 		}
 		if err := sortSong(path, dst, true); err != nil {
 			slog.Error("Failed to sort single file", "file", path, "err", err)
-			os.Exit(1)
+			return err
 		}
-		return
+		return nil
 	}
 
 	// Handle directory
@@ -70,6 +72,7 @@ func Sort(dst, path string) {
 	})
 
 	if err != nil {
-		os.Exit(1)
+		return err
 	}
+	return nil
 }