diff --git a/tracer.py b/tracer.py
index 7f08f09..66d183b 100755
--- a/tracer.py
+++ b/tracer.py
@@ -40,7 +40,9 @@ def populate():
         if os.path.isdir(d):
             for p in os.listdir(d):
                 rule = d + "/" + p
-                name = p.replace(".json", "")
+                name, ext = os.path.splitext(p)
+                if p.startswith(".") or ext not in (".json", ""): # dot file or not .json or extensionless
+                    continue # skip file
                 # print(p, rule, name)
                 if p in DB:
                     DB[name].append(grammar(load_rules(rule)))