How to prevent AutoCAD from echo commands from AutoLisp?

[hisham_tannous]

Hi guys, I have a Python program, and an AutoLISP code. I want to prevent users from loading the *.lsp code from AutoCAD using APPLOAD and instead force them to load it only from Python program. I searched a lot and I'm frustrated after a week of trial.

This is what I'm doing
mylisp.lsp:

(defun envvar ()
(if (/= (getenv "ENVVAR") "value")       ; compare it to value
    (progn
        (alert "This file can only be loaded from the Python script.")
        (exit))))

(envvr)
; rest of lisp code goes here such that if they load it without python it will fail otherwise it will succeed ​

my python code is:

    global acad
    acad = Autocad(create_if_not_exists=True)
    
    acad.doc.SendCommand('(setenv "ENVVAR" "value")\n')
    time.sleep(1)
    acad.doc.SendCommand('APPLOAD ') #loading the script after setting ENVVAR
# the rest of python code

everything works perfectly, the problem is, when I set the ENVVAR from python (line 4 above), it echoes everything in AutoCAD command line (shows the entire command with the value), I tried many things like adding a (princ) or some other things but I don't want the command to print the secret data for the ENVVAR when I set it.
How can I prevent it from echoing this. Or if you guys have a better idea for preventing people to load the lisp file without python code !

Thanks alot 

[paullimapa]

What if you use python to update the registry where AutoCAD would see your environment variable?

This thread should give you an idea where they are stored

[ec-cad]

(setvar "CMDECHO" 0)

ECCAD