To output the 10 largest directories in /, sorted in ascending size order, use the following command:

du -ko /|sort -n | tail -10

To find all plain files (not block, character, symbolic links, and so on) in a / file system larger than 1,000 512-byte blocks (approximately 500 Kbytes) and sort on field 7 (file size) while numerically ignoring leading blanks, do this:

find / -size +1000 -type f -ls | sort -k 7,7 -n