diff --git a/frontends/PyCDE/src/pycde/testing.py b/frontends/PyCDE/src/pycde/testing.py
index 2dd27935fcfd..19cfe773afc9 100644
--- a/frontends/PyCDE/src/pycde/testing.py
+++ b/frontends/PyCDE/src/pycde/testing.py
@@ -123,7 +123,7 @@ def extra_compile_args(self, pycde_system: System):
     # lives easier and create a minimum timescale through the command-line.
     cmd_file = os.path.join(pycde_system.output_directory, "cmds.f")
     with open(cmd_file, "w+") as f:
-      f.write("+timescale+1ns/1ps")
+      f.write("+timescale+1ns/1ps\n")
 
     return [f"-f{cmd_file}"]