This article was first written in August 2004 for the BeezNest technical website (http://glasnost.beeznest.org/articles/150).
I can often be useful to track down disk usage in Maildir format. For example, looking at Trash folder size of all your mailboxes, provided you are using Maildirs located in users’ homes:
# cd /home; for i in *; do if [ -d $i/Maildir/.Trash ];then du -s $i/Maildir/.Trash; fi; done | sort -n
It will give you something like (provided you have both mailboxes: titi and grosminet):
104 titi/Maildir/.Trash 108 grosminet/Maildir/.Trash