GrepCode - GrepCode.com is a code search engine built by developers for developers to search and browse open...
Sourcegraph - Sourcegraph is a free, self-hosted code search and intelligence server that helps developers find, review, understand, and debug code. Use it with any Git code host for teams from 1 to 10,000+.
OpenGrok - OpenGrok is a fast and usable source code search and cross reference engine.
searchcode - A source code search engine
Open HUB - Open HUB is an open source directory that anyone can edit.
Text Sherlock - Provides a fast, easy to install and use search engine for text but, mostly for source code.