xdu is described as 'Disk usage or other tree data display program. Typical usage: du -xm / | xdu -n' and is an app in the OS & Utilities category. There are more than 10 alternatives to xdu for a variety of platforms, including Windows, Linux, Mac, BSD and KDE. The best alternative is WinDirStat, which is both free and Open Source. Other great apps like xdu are TreeSize (Paid), Baobab Disk Usage Analyzer (Free, Open Source), ncdu (Free, Open Source) and JDiskReport (Free).
WhatSize is a simple tool that allows the user to quickly measure the size in bytes of a given folder and all subfolders and files within it. You would be surprised at how many useless files might be laying around on your hard disks.
xdiskusage is a user-friendly program to show you what is using up all your disk space. It is based on the design of xhttp://alternativeto.net/software/xdu/ written by Phillip C. Dykstra <dykstra at ieee dot org & gt.