AquaGrep for Mac

From publicspace.net:

AquaGrep is a Mac OS X front-end to the Unix grep text search utility.

Grep's powerful and versatile text search features, its speed and its straight-forward working principle have made it one of the most heavily used Unix command line tools.

You can use grep to search through HTML and text files, analyse web server logs, etc.. It is the ideal companion for the Mac OS X webmaster and all other other users who require powerful text search features.

While Mac OS X comes with a full-featured grep implementation in its Darwin kernel, command line tools are notoriously difficult to use and do not offer the kind of user experience that Macintosh users have come to expect over the last 15 years.