Edit: Come on. Downvotes for this? Honestly... It's HN, not StackOverflow. You don't mark questions as "off-topic" unless they're trolling...
Edit: Come on. Downvotes for this? Honestly... It's HN, not StackOverflow. You don't mark questions as "off-topic" unless they're trolling...
grep is defined for POSIX after all: http://pubs.opengroup.org/onlinepubs/009695399/utilities/gre...
I also suspect (without looking) that there are obscure (but occasionally useful) grep features that ack doesn't support.
Edit: MattJ100 made a more clear point while I was responding.
The other points are quite understandable and correct though. It's always best to at least be familiar with standard tools, even if you want to use an slightly different version for yourself.
One example of a useful feature of grep: "grep --line-buffered" to grep with no buffering in a pipeline.
"ACK is a highly versatile Kanji code converter. ACK can do reciprocal conversion among Japanese EUC"
This is probably why I don't use ack - never heard of it, not available on any system I use, and the dpkg repository has something that has nothing to do with grep.
Enough of an answer?
First time I've heard of it. Thanks. Only been grepping my way around for the last dozen years or so ...
1. Because all the cool kids are doing it.
2. Because I hate Perl.