"If you haven't been paying attention to GNU grep recently, you
should be happily surprised by some of the new features and options
that have come about with the 2.5 series. They bring it
functionality you can't get anywhere else--including the ability to
output only matched patterns (not lines), color output, and new
file and directory options.
"Granted, the addition of this feature set caused a number of
bugs that made it necessary to rewrite part of the code, but the
latest 2.5.1a bugfix release is eminently usable..."