alias2html used to convert the postfix mail alias into html pages.

By default, the alias file path is "/usr/local/etc/postfix/aliases". You can change it to your path by vim alias2html and modify path = "/usr/local/etc/postfix/aliases" to your real file

the generated html will be showed in standard output

so you have to

./alias2html > output.html

and put the output.html to somewhere you want people to access.