diff --git a/common/read_sources.py b/common/read_sources.py
index 32d160d..169895c 100755
--- a/common/read_sources.py
+++ b/common/read_sources.py
@@ -167,6 +167,8 @@ def source_tokenizer(buffer):
         start_index = 0
         is_blank_from_zero, previous, current = True, "", ""
         ln = line.expandtabs(4)
+        idx_comment = ln.find("#")
+        ln = ln[:idx_comment] if idx_comment > -1 else ln
         for pos, current in enumerate(ln):
             # check for indentation
             if current == " " and previous in ["", " "] and start_index == 0:
diff --git a/envs/bin/run b/envs/bin/run
index af7e8d1..edd38da 100755
--- a/envs/bin/run
+++ b/envs/bin/run
@@ -108,6 +108,9 @@ if __name__ == "__main__":
     parser.add_argument(
         "-c", "--clean", help="clean working directory", action="store_true", default=False
     )
+    parser.add_argument(
+        "-l", "--custom_log", help="use custom `log_*", action="store_true", default=False
+    )
     parser.add_argument(
         "-b",
         "--batch",
@@ -198,7 +201,7 @@ if __name__ == "__main__":
 
     # run a simulation
     if args.sim:
-        type, files, params = prepare_task(type="sim")
+        type, files, params = prepare_task(type="sim", use_custom_logger=args.custom_log)
         # load the simulator script
         if type is SimType.DIGITAL:
             tool_name = Config.tools.get("DIG_SIMULATOR")