Need help with DB Design...

I'm going to make an app which is going to use a lot of text files....

I want to be able to search all of the text files by line, for a word, and then display the results of each line w/ that word in it, but I figure searching text files would be hideously slow...

So I figure, in order to make it viable, I'm going to need to find some way to like store the data in memory possibly?

I need some way to index the search maybe, but to be honest I'm clueless where to begin. =(

Thoughts & Suggestions?