This PHP script generates index.html tables based on all items in a directory or on a text file with url and subject information. All you need is the php-cli package, no need for a PHP server installation.
The text file should have the following line format:
file.html:Document for accounting
to generate such file in linux:
$ grep -a ^Subject: *|sort -k 2|sed 's/Subject: //g;s/\r//g' >titles.txt
Example: