Linux - Linux has a very efficient file system but to think that when you delete files or clear cache that the file system won’t become fragmented or have gaps between files is purely misleading. Many forums on the web will tell you that it is not necessary. Think about it….OK now, you can download defrag utilities for Ubuntu. Defrag for Ubuntu
Windows – The best defragging utility now is Auslogics. This freeware out performs any other defrag utility.