make cut output a certain term when no delimiter found

I am looking for extensions of files and cut simply gives the filename if the file has no extension so I am looking to make cut give a "extensionless" when no '.' is found I am using this as a refrence: https://stackoverflow.com/questions/1842254/how-can-i-find-all-of-the-distinct-file-extensions-in-a-folder-hierarchy the answers that ignore the files without extensions were no good as I needed to find those too