The CLI interface has a .load command with which to load extensions. It also has a -init FILENAME invocation option which can be used to run a set of commands on startup. With those alone, you could get the functionality you seek if you are willing to write the extension. It is reasonably easy to do. There are some extensions which are build into the shell, but they are structured and initialized as if they resided in a just-loaded DLL. If you wanted to build an extension of your own into a customized shell, that too would be simple to do, with examples of similar "modification" already in the distribution source.