gracefully handle PermissionError

findduplicatedirs.py

@@ -50,9 +50,12 @@ for (i, (dirpath, dirnames, filenames)) in enumerate(directorywalk):
             h.update(os.readlink(filename).encode('utf8', 'surrogateescape'))
         elif os.path.isfile(filename):
             du += os.path.getsize(filename)
+            try:
                 with open(filename, 'rb') as f:
                     for chunk in iter(lambda: f.read(4096), b''):
                         h.update(chunk)
+            except PermissionError:
+                pass
     # process all directories
     for dirname in sorted(dirnames):
         h.update(dirname.encode('utf8', 'surrogateescape'))