When external quota commands are being used, the program set in this option can be called by Virtualmin to fetch the quota for a single user. It is called with a single parameter - the full Unix username, and must output a single line containing the following space-separated fields :

1. Current quota used in 1 kB blocks.
2. The soft quota in 1 kB blocks, or 0 for unlimited.
3. The hard quota in 1 kB blocks, or 0 for unlimited.

If this command is not set on the Module Config page, Virtualmin will use the Command to list user quotas instead.