Let's say you're waiting for a client to upload a file to you, or perhaps you need to know the moment that accounting is done with a particular report. In both cases you can't rely on them to email you that they have saved the file in the appropriate location. There's an easy way to watch for this.

iWatch is a great little utility that tries to be a simple Tripwire for monitoring security, but is really best used in the above situations. It will monitor a file or directory, recursively or not, for various changes and email a particular recipient when the change occurs. It relies on Postfix for sending outbound notices.

The beauty of iWatch is it's ability to only monitor for certain events. For instance, I want to know when a file is added to a directory, but I don't care about subsequent modifications or deletions to that file. iWatch can monitor just the one event (or any combination of events including mounting of partitions.)

In daemon mode, it is configured with a simple XML file. The documentation appears sparse, but it's really very easy to figure out.