DocFetcher - DocFetcher is a portable German/English open source desktop search application.
The Silver Searcher - A code searching tool similar to ack, with a focus on speed.
Agent Ransack - Agent Ransack is a tool for finding files and information on your hard drive fast and efficiently.
grep - grep is a command-line utility for searching plain-text data sets for lines matching a regular...
dtsearch - dtSearch - The Smart Choice for Text Retrieval since 1991.
ack - Ack is designed as a standalone (one perl file) replacement for 99% of the uses of grep.