redgrep
About
redgrep is a grep based on regular expression derivatives. That is, it uses regular expression derivatives to construct the DFA. It then uses LLVM to JIT the DFA.
Since regular expression derivatives permit the three basic Boolean operations of disjunction (|), conjunction (&) and complement (!), redgrep enables you to write very powerful regular expressions very easily and guarantees to match them in linear time.
Building
You must have GNU make, GNU bison and either GCC or Clang.
redgrep follows the "latest and greatest" in LLVM development, so you should check out the source from Subversion or Git, then configure, build, check and install as per the instructions. (Debian and Ubuntu users may prefer to install the nightly packages instead.)
You should set the LLVM_CONFIG environment variable appropriately when
you run make.
Contact
Disclaimer
This is not an official Google product.