swish-e is a great search tool. It even has a nice Swish::API in perl. apache.org use it for instance to search their site. It will index and search any text file and there are plugins for all sorts of formats to convert them to text for indexing. Index searches are the way to go rather than grepping every file every time you search. With swish-e the core code is C, it handles stemming and indexing for you and you get a nice stable solution with a solid XS API.