How to run MestReNova quietly (on Linux)

sim_1hnmr.py

def sim_1hnmr(smiles: str):
    if not smiles:
        return

    if not MolFromSmiles(smiles):
        return

    smiles = CanonSmiles(smiles)

    with tempfile.NamedTemporaryFile(mode='wt', suffix=".csv") as peaks_file:
        display_num = os.getpid()  # Use unique display per process

        # Start virtual X server for this process
        xvfb_cmd = f"Xvfb :{display_num} -screen 0 1024x768x24 2> /dev/null &"
        os.system(xvfb_cmd)

        # Run MestReNova with isolated display
        env = os.environ.copy()
        env["DISPLAY"] = f":{display_num}"

        subprocess.run(
            args=[MRN_EXE, MRN_1H_SCRIPT, "-sf", f"predict_1H,{smiles},{peaks_file.name}"],
            env=env,
            stderr=subprocess.DEVNULL,
        )

        peaks_file.flush()

        # Stop Xvfb after running MestReNova
        os.system(f"pkill -f 'Xvfb :{display_num}'")

        with open(peaks_file.name, mode='rt') as fd:
            return fd.read()