When external quota commands are being used, the program set in this option will be called when Virtualmin needs to find existing user quotas. It is not called with any parameters, but must output one line of text per user, with each line containing space-separated fields. The fields on each row must be :

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