sift is a fast and powerful open source alternative to grep. It comes as a single executable with no external dependencies - just download it and you are ready to go.

Most of the existing tools for searching through big amounts of text are either fast but inflexible (the original grep) or slightly more flexible but slow or complicated to install.

sift is an alternative that aims for both speed and flexibility - i.e. adding features while trying to reach (or even surpass) the performance of the original grep.
The additional features include multiline matching, conditions (e.g. match A only when preceded by B within X lines) and full multicore support.

sift is not tailored towards a specific use case (like system administration or code development/auditing), but you can customize it to your needs through a global or local configuration file. Don't want to search through .git directories? Just execute sift --exclude-dirs '.git' --write-config and you are done.

Please see the features and samples to get a better impression of what you can do with sift.

The following benchmarks show the performance of sift. While speed is not everything, it is quite a difference whether you get your results after 2 seconds or 2 minutes, especially when you are grepping through many files over and over (e.g. when searching in large source code repositories or big log files).
These results were achieved even though sift introduces new features that other tools do not have, like conditions and multiline matching.

In this comparision, all tools were configured to search the complete test data. Of course sift too can be configured to only search in specific paths/files/etc., but the aim was being fast while searching through the complete test data.

All searches were performed with the complete data files cached by the operating system. Three runs per test were performed and the best result was taken.
The weblog searches were done on a big server, while the rest was done on a desktop system.