thanks sinc....
but i can't use undefine command..
because as you said...users can put the " . " symbol.
or use "redefine".
If that's important, then the solution you are trying to create probably won't work either. Lisp is not very robust, and is not designed to be used as a "user shell" inside of Autocad. It would be very easy for a command to error in such a way that your Lisp routine gets interrupted, and the user is right back at a normal Autocad prompt. Your user would have to manually restart your little ING thing, and it sounds like you can't trust your users to do this.
I don't think Autocad has any built-in support for what you are trying to do, and I don't think it's possible to create a robust solution in Lisp. There might be a way in some other language, but I doubt that, too. Autocad is designed so that the built-in commands can always be accessed, even if they are redefined or undefined, and I can't think of any way of changing that. I suspect it would be a challenge even if you write your own complete vertical app and run "Autocad inside".
There may be some sort of incredibly clever "trick" you can do and get the results you're after, but I can't think of what it would be... The usual solution is to just train your users...
