In the directory you want to index, run:
for i in G M K; do du -ah | grep ^[0-9\.]*$i | sort -nr -k 1; done > ~/Desktop/files.txt
It will create a file on your Desktop with the all the names of the files and directories sorted from largest to smallest.
Via How Do I Find The Largest Top 10 Files and Directories On a Linux / UNIX / BSD?.