This depends on the implementation, not the language. With the great majority of implementation this is true, though. LispWorks and Allegro CL have support for this, but I don't know the real size of the executables, because I've never used them. The problem is that you have to carry the runtime together with the application, because if your application uses 'eval, then to execute it you need a compiler and all the runtime. The comparision with 'grep' isn't fair: grep uses the C runtime that comes pre-installed on the system. You dont' notice it, but it is there and it is quite big. If you had a pre-installed lisp system, then you could deliver small fast starting executables.
> grep uses the C runtime that comes pre-installed on the system.
Quite right. The fact that the OS itself is (usually) written in C means that nearly every OS-using computer has a C runtime.
As an aside, consider executable file sizes in the Windows world, where the OS does not provide its C library to other programs. Many programs in Windows include their own versions of the C library, increasing their sizes.
