Ack - better than grep, a power search tool for programmers | Hacker News Reader

Ack - better than grep, a power search tool for programmers

betterthangrep.com

152 pointsmustpax33 comments

Worth mentioning that there is another program in the Ubuntu repos called ack. They've renamed this to ack-grep (don't use Debian so I don't know if the naming convention was pulled in from Debian Unstable or added by the Ubuntu devs).

I'm pretty sure it's the same on debian.

First thing that went to my .bashrc was:

alias ack='ack-grep'

Correct, ack - Kanji code converter is the one I just installed by not reading HN posting first...

Previous discussion at

http://news.ycombinator.com/item?id=223977

http://news.ycombinator.com/item?id=830522

If you are interested, I've posted an interactive shell for ack (and grep) here:

http://github.com/aristus/ack-shell

    $ acksh ack

    1) ./ack-shell/ack-shell
      2:   ## iack (interactive ack)
     15:   prompt = 'ack> '
     44:   cmdline[0] = 'ack'
 
    ack> open 1 44

I've been using Ack for a while, and really like it. It saves a few keystrokes, and gives you a nice (colored) output of the results with line numbers as well:

> grep -r unicorn .

./config/unicorn/unicorn_build.rb: logger unicorn_logger

./config/unicorn/unicorn_build.rb: old_pid = '/home/rails/xxxxx/current/tmp/pids/unicorn.pid.oldbin

./config/unicorn/unicorn_production.rb: '/home/rails/xxxxx/current/tmp/pids/unicorn.pid.oldbin'

> ack unicorn

config/unicorn/unicorn_build.rb

10:# logger unicorn_logger

14:# old_pid = '/home/rails/xxxxx/current/tmp/pids/unicorn.pid.oldbin'

config/unicorn/unicorn_production.rb

15:# '/home/rails/xxxxx/current/tmp/pids/unicorn.pid.oldbin'

One day I'll grok the formatting for HN. Just not today obviously :/

FWIW "grep --color -n" does the same thing.

Ah, thank you! Can't believe I haven't been using the -n flag all this time. These flags don't do "exactly" the same thing as Ack, as Ack actually breaks it down by distinct sections, with newlines. It's a bit easier on the eyes.

Not if you're using SVN. Or if someone stuck a 24MB SQL data-dump with extended inserts somewhere, that has the word "unicorn" in it.

The newest version of grep has --exclude-dir, which handles .svn folders just fine.

A nice alternative to my decidedly low-tech approach:

  (in ~/.zshrc)
  # 'ff' command -- find string in files with a specified suffix
  ff() {
    [[ -n $1 && -n $2 ]] || {
      echo "Usage $0 [suffix] [string]"
      echo "Where"
      echo "  suffix  file suffix (without wildcards)"
      echo "  string  string to search for (quote if spaces)"
      return
    }
    find . -name \*$1 -exec grep -Hn $2 "{}" \; | less -RFX
  }

Has colorized output, and only pages (with less) when there is more than one page to show.

The time I sometimes lose reading HN pays off when I find stuff like this. BTW the type heuristics is good enough to look inside of files to determine the type: doing 'ack --python pattern' WILL DO look into python files that have no extension (like the toplevel module for instance).

I just use 'git grep' to only grep in tracked files. It's worthwhile to learn that tool, for example to learn how you can grep in older revisions.

How does one add a custom type to ack and get it to stick? Per the man page, I tried:

     ack --type-set objj=.j

Doesn't work. I can append that to a query:

     ack CPWindowController --type-set objj=".j"

And it will search .j files for CPWindowController, but then it immediately forgets .j and the objj type.

Create a .ackrc file in your home directory. For you, it will contain:

  --type-set
  objj=.j

I found this on the ack-grep man-page in Ubuntu. You can set the ACKRC environment variable to give it a different directory (besides ~) to search for your .ackrc. Each line of the .ackrc is a command-line arg that will be prepended to any specified arguments every time you run ack-grep. If you don't want those arguments for a particular query, pass the --noenv flag to ignore the .ackrc. HTH!

Thanks!

Just something I had a hard time figuring out and seems poorly documented:

    --type-set=scala=.scala # works in .ackrc
    --type-set scala=.scala # doesn't work in .ackrc

...despite the version with one equals being correct command-line sequence. Only seems to matter if you want each flag on a single line in your .ackrc file. Might not be true for everyone.

I have a wrapper around find that does things like filter out .svn directories. I sometimes use ack for simple searches, but find/xargs/grep together are faster and more explicit in my experience.

The Ack Textmate bundle on the site is pretty awesome as well.

For the emacs folk, I use this: http://repo.or.cz/w/ShellArchive.git?a=blob_plain;hb=HEAD;f=...

But there's also (last I looked, may be more now): http://www.rooijan.za.net/?q=ack_el

I love the Textmate bundle. I actually extended it a bit so that you could filter for file types, which might be handy to some folks: http://github.com/adamsanderson/ack-tmbundle

Is it significantly better than M-x rgrep in Emacs?

Yes.

(M-x rgrep in Emacs == grep -r everywhere else)

Not quite.

Emacs' rgrep DIR PATTERN REGEX translates to

  find DIR \( -path \*/SCCS -o -path \*/RCS -o -path \*/CVS \
  -o -path \*/MCVS -o -path \*/.svn -o -path \*/.git \
  -o -path \*/.hg -o -path \*/.bzr -o -path \*/_MTN \
  -o -path \*/_darcs -o -path \*/\{arch\} \) -prune \
  -o  -type f \( -name PATTERN \) -print0 \
  | xargs -0 -e grep -i -nH -e REGEX

See also http://www.rooijan.za.net/?q=ack_el - you can compare each from within emacs.

Being able to use --output with your matched subexpressions is worth going through the trouble of installing it.

python has grin http://pypi.python.org/pypi/grin

And ruby has rak: http://rak.rubyforge.org/

Before I switched to ack, I used glark. http://www.incava.org/projects/glark/

Fortunately, your search tool doesn't need to be written in the same language your project is.

That being said, performance comparisons would be interesting. Not necessarily from a "which is better" standpoint, but from a "what can these projects borrow from each other", assuming it's not a straight port.

Love it and have used it for years, A++ would buy again!!

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