File Changes Notifier

Scenario

You are the administrator of a system and have multiple logging files from different applications at your disposal. You want to be notified every time new information appears in any of these files, and at the same time, you want to be able to add new monitoring targets throughout the runtime of this monitor.

All answers should be justified.

Question

Can you suggest a simple method or pseudocode to solve this dilemma? (hint: file operations).