Anyone aware of a script or software that watches for file changes and alerts?

Looking for software that I can install on a webserver and monitor certain folders. For example I want to be able to monitor /web folders and subfolders for all our websites and have a flexible way of alerting admins or the end users. Would be good to be able to exclude certain log files or cache files that get updated, or specify only *.php and *.css files and anything else that can get executed.

Have been looking around on google and not finding what I am looking for. Even a commercial product would be OK.
Was hoping someone had already implemented something like this and could give some hints.

Thanks

 

The last part of the first post in this thread has a sample of inotify script being used.

 

Or easier to use, I think, is Monit; https://mmonit.com/monit/documentation/#FILE-CHECKSUM-TEST
Example scripts for monit are there too.

 

After looking around I see inotify is not recursive and it looks like a lot more work then I want.
Think I will give ISPProtect a try. As new websites gets added they are automatically tested as far as I can tell from reading about it on their website.

Thanks!