I was using a log watcher that could run a command on a regex match, but I remember having an elaborate .htaccess that would shell out all kinds of things... many ways to tie them together, all very hacky.

thank you for this insight.

it might not even be that hacky to be honest. in some ways modern log aggregation isn’t that different, just insulated by more steps and safe guards. less moos though.

I'm trying to imagine what was popular back then. A Perl CGI script?

Perhaps showing my age, but that is still how I would do it. It's dead simple.

Even simpler is tailing the access log into a script that makes sound upon matching the correct path.

Years ago I had /var/www/lights_on.sh that turned lights on in my room. Only hardened against RCE by Wi-Fi password, but was possible. It broke later. The real problem was that browsers sometimes prefetched it.