TIL: #Vim can do :w >> filename to _append_ to a file. (You can omit "filename" to append to the current file.) Also, :w accepts a range, so if you want to append only a few lines from the current buffer (e.g. by selecting them in visual mode), you can do that. And :w also accepts a range when _not_ appending, allowing you to save only a selection of lines in the current buffer to the current file. (You might need to use :w! if it's an existing file, to protect you from fuckups.)