我发现了各种开源工具（例如goaccess.io）可以将access.log或other_vhosts_access.log转化为唯一访客分析：
739 visits 16/Oct/2016
804 visits 15/Oct/2016
838 visits 14/Oct/2016
966 visits 13/Oct/2016
但由于我的other_vhosts_access.log包含虚拟主机：
www.siteb.com:80 216.244.x.x - - [17/Oct/2016:07:26:23 +0200] "GET ...
www.siteb.com:80 206.14.x.x - - [17/Oct/2016:07:26:23 +0200] "GET ...
www.sitec.com:80 189.18.x.x - - [17/Oct/2016:07:21:43 +0200] "GET ...
是否有分析工具可以提供每个主机的详细信息，如下所示：
739 visits 16/Oct/2016
|--- sitea.com 140
|--- siteb.com 127
|--- sitec.com 472
804 visits 15/Oct/2016
|--- sitea.com 205
|--- siteb.com 120
|--- sitec.com 479
？