diff --git a/interp.py b/interp.py
index 79944e1..9b0f6f9 100644
--- a/interp.py
+++ b/interp.py
@@ -65,9 +65,10 @@
             return None
 
     def run(self, ast):
+        ret = None
         for command in ast:
-            self.run_command(command)
-        return None
+            ret = self.run_command(command)
+        return ret
 
 def run_ast(ast):
     env = {