diff --git a/src/python/devtest/os/test/ListCmd.py b/src/python/devtest/os/test/ListCmd.py
index a7a674e..b233b50 100644
--- a/src/python/devtest/os/test/ListCmd.py
+++ b/src/python/devtest/os/test/ListCmd.py
@@ -276,7 +276,7 @@ class ListCmd(TestCase): # export
             raise Exception('Failed to compile regex ({}): >{}<'.format(e, str(re_str)))
         return list(filter(None, [parse_line(l, fields) for l in lines]))
 
-    def _eval(self, output, features, header=None):
+    def _eval(self, output, features, header=None, tstamp=None):
 
         def format_rows(rows, quotes=False):
             #def cmp(r1, r2):
@@ -361,6 +361,8 @@ class ListCmd(TestCase): # export
         feature_diff = set(features) - last_features
         if self.__write_response and len(feature_diff):
             response_path = self.refpath[0] + '.bad'
+            if tstamp is not None:
+                response_path += '-' + tstamp
             feature_diff_str = ', '.join(['"{}"'.format(f) for f in feature_diff])
             with open(response_path, "w") as f:
                 slog(INFO, 'Writing feature diff to "{}"'.format(response_path))
@@ -388,7 +390,7 @@ class ListCmd(TestCase): # export
         else:
             header = '# ' + cmd + '\n'
             header += '# features: {}\n'.format(' '.join(env.features))
-        return self._eval(output, env.features, header=header)
+        return self._eval(output, env.features, header=header, tstamp=env.time_stamp)
 
     def dump(self, prio, *args, **kwargs):
         caller = kwargs['caller'] if 'caller' in kwargs.keys() else get_caller_pos(1)