The quot command provides a quick measure of the disk usage of multiple users on a filesystem.
The quote command must be run as or with the privileges of root. The following is sample output for the quot command:
In this output, the raw device of the filesystem is shown first. The username is provided, if known. The numeric uids 5115 and 317 own files but are unassociated with a username in /etc/passwd as is common when files are untarred from another system.
The -a option can be used in place of the filesystem to check (/usr in that example) and will make quot iterate through all mounted filesystems. The -f option will add a middle column containing the number of files owned by each user.
The quot command could be very useful when a filesystem fills suddenly as it can quickly determine what user to flog or which application has to be checked.