If you have a file called "todo.<something else>" in your home directory (like say todo.rest), and you accidentally type "yagtd todo<TAB><RETURN>", you end up running "yagtd todo.". yagtd correctly notices that "yagtd." does not exist, so it doesn't load anything. On exit, it writes its current state (which is empty) to "todo.txt", so you end up truncating todo.txt.

If yagtd is invoked with the name of a non-existing file, I could perhaps create said file and also save its state to that file on exit instead?