Had an odd issue of locating a client server issue where there was a problem large number of small files.
find . -type d | cut -d/ -f 2 | uniq -c
user@server:/home/client/domains# find . -type d | cut -d/ -f 2 | uniq -c 1 . 2004 sub1.client.com 3487 sub2.client.com 249516 sub3.client.com
This showed that the last subdomain had a large number of files. It eventually transpired it was a lot of session files created by a PHP application.