The proposed fix is wrong. > This is a lesson on why not to use static backup filenames. Yes, that would address this bug, and this bug only. What if there's

The proposed fix is wrong. > This is a lesson on why not to use static backup filenames. Yes, that would address this bug, and this bug only. What if there's another bug? Or the file system is full? Or `ed` gets kill -9'd? Or the PC loses power? Assuming it's possible to predict every single failure mode is foolish. It's better to make a system safe by default. In the case of `ed`, simply periodically store the text buffer in a file and restore from it on startup.