Can someone recommend a simple, efficient way to monitor a list of various web pages (or in some cases, a hierarchy of pages) for changes, and then send an alert mentioning which pages have changed? I can think of one method, where wget is used to mirror the pages in question, but am unsure as to a reasonable method for determining if new material has been copied over. Would be necessary to keep two parallel directories: one for the old mirrored copy, and one for the new, and then compare the mirrored trees for differences/updates? Or might this info. be extracted from wget's log as it mirrors the pages?
(Basically, I want to monitor some news/research sites, which change from time to time, but not very often, for changes and to be sent mail when those pages change. Ideally, I'd like to see a brief excerpt from the changes, or the changed pages, but my guess is that wouldn't be too simple. <g>)
