How to delete a file from plain Lisp?

I normally use this line to delete a file from Lisp:

       (command "shell" (strcat "del " "1run.txt"))

I want to use a specify a drive also, like this:

      (command "shell" (strcat "del " "H:/1run.txt"))

But it does not work. The file is not deleted.

I am using Bricscad V6, so I assume that the VL delete function is not usable.

Does anyone know how I can solve this?