剛在 awstats 的網頁上找到了計算 per directory 量的方法：
ExtraSectionName1="Directory under /pub"
ExtraSectionCodeFilter1="200 304"
ExtraSectionCondition1="URL,^\/vinum\/services\/ftp\/pub\/.*"
ExtraSectionFirstColumnTitle1="Directory name"
ExtraSectionFirstColumnValues1="URL,^\/vinum\/services\/ftp\/pub\/([\w]+)\/"
ExtraSectionStatTypes1=PHB
MaxNbOfExtra1=50
MinHitExtra1=1