ack 3 is now in beta

ack 2.999_06 has been released to beta. It is feature complete, but we still will be working on speed improvements. Compare ack's features to other grep-like programs in our handy feature comparison chart.

You can get the beta through one of two methods:

We welcome you to contribute or report issues on .

What's new in ack 3?

New --proximate option groups matches near each other

A new option --proximate=N groups together lines of output that are within N lines of each other in the file. This is useful when looking for matches that are related to each other.

For example, these results:

    15: First match
    18: Second match
    19: Third match
    37: Fourth match

would look like this with --proximate=1.

    15: First match

    18: Second match
    19: Third match

    37: Fourth match

Improved and incompatible -w option

The -w option, which tells ack to only find whole-word matches, did not always work if your pattern began or ended with puncutation. ack would make guesses as to what your intent was, but it was not well-defined. Now, ack disallows regexes that begin or end with non-word characters.

This means that if you use ack -w foo:, the new ack will not allow it, whereas ack 2.x would.

Added -S as a synonym for --smart-case

For those without --smart-case always on, the -S will be easier for when you do want to use it.

Smart-case matching makes ack do a case-insensitive search unless the pattern being matched has a capital letter in it.

Added -I to force case-sensitivity

If you use --smart-case in your .ackrc, you can use -I to force case-sensitivity instead of having to use --no-smart-case (which still works).

Significant speed improvements

Run times for ack 3 compared to ack 2.22 are 30-40% faster because of removal of unused infrastructure for plugins.