The Silver Searcher

A code searching tool similar to ack, with a focus on speed.

Do you know C? I invite you to pair with me to help me get to Ag 1.0.

What's so great about Ag?

• It is an order of magnitude faster than ack.
• It ignores file patterns from your .gitignore and .hgignore.
• If there are files in your source repo you don't want to search, just add their patterns to a .agignore file. (*cough* extern *cough*)
• The command name is 33% shorter than ack, and all keys are on the home row!

Ag is quite stable now. Most changes are new features, minor bug fixes, or performance improvements. It's much faster than Ack in my benchmarks:

ack test_blah ~/code/  104.66s user 4.82s system 99% cpu 1:50.03 total

ag test_blah ~/code/  4.67s user 4.58s system 286% cpu 3.227 total

Ack and Ag found the same results, but Ag was 34x faster (3.2 seconds vs 110 seconds). My ~/code directory is about 8GB. Thanks to git/hg/svn-ignore, Ag only searched 700MB of that.

There are also graphs of performance across releases.

How is it so fast?

• Ag uses Pthreads to take advantage of multiple CPU cores and search files in parallel.
• Files are mmap()ed instead of read into a buffer.
• Literal string searching uses Boyer-Moore strstr.
• Regex searching uses PCRE's JIT compiler (if Ag is built with PCRE >=8.21).
• Ag calls pcre_study() before executing the same regex on every file.
• Instead of calling fnmatch() on every pattern in your ignore files, non-regex patterns are loaded into arrays and binary searched.

I've written several blog posts showing how I've improved performance. These include how I added pthreads, wrote my own scandir(), benchmarked every revision to find performance regressions, and profiled with gprof and Valgrind.

Installing

OS X

brew install the_silver_searcher

or

port install the_silver_searcher

Linux

• Ubuntu >= 13.10 (Saucy) or Debian >= 8 (Jessie)

    apt-get install silversearcher-ag
  

• Fedora 19+

    yum install the_silver_searcher
  

• RHEL7+

    rpm -Uvh http://download.fedoraproject.org/pub/epel/7/x86_64/e/epel-release-7-5.noarch.rpm
    yum install the_silver_searcher
  

• Gentoo

    emerge the_silver_searcher
  

• Arch

    pacman -S the_silver_searcher
  

• Slackware

    sbopkg -i the_silver_searcher
  

BSD

• FreeBSD

    pkg install the_silver_searcher
  

• OpenBSD/NetBSD

    pkg_add the_silver_searcher
  

Building from source

Building master

1. Install dependencies (Automake, pkg-config, PCRE, LZMA):

   • OS X:

       brew install automake pkg-config pcre xz
     

     or

       port install automake pkgconfig pcre xz
     

   • Ubuntu/Debian:

       apt-get install -y automake pkg-config libpcre3-dev zlib1g-dev liblzma-dev
     

   • Fedora:

       yum -y install pkgconfig automake gcc zlib-devel pcre-devel xz-devel
     

   • CentOS:

       yum -y groupinstall "Development Tools"
       yum -y install pcre-devel xz-devel
     

   • Windows: It's complicated. See this wiki page.

2. Run the build script (which just runs aclocal, automake, etc):

    ./build.sh
   

On Windows:

    mingw32-make -f Makefile.w32

3. Make install:

    sudo make install
   

Building a release tarball

Building release tarballs requires the same dependencies, except for automake and pkg-config. Once you've installed the dependencies, just run:

./configure
make
make install

You may need to use sudo or run as root for the make install.

Editor Integration

Vim

You can use Ag with [ack.vim][] by adding the following line to your .vimrc:

let g:ackprg = 'ag --nogroup --nocolor --column'

or:

let g:ackprg = 'ag --vimgrep'

Which has the same effect but will report every match on the line.

There's also a fork of ack.vim tailored for use with Ag: [ag.vim][] [ack.vim]: https://github.com/mileszs/ack.vim [ag.vim]: https://github.com/rking/ag.vim

Emacs

You can use ag.el as an Emacs fronted to Ag. See also: helm-ag.

TextMate

TextMate users can use Ag with my fork of the popular AckMate plugin, which lets you use both Ack and Ag for searching. If you already have AckMate you just want to replace Ack with Ag, move or delete "~/Library/Application Support/TextMate/PlugIns/AckMate.tmplugin/Contents/Resources/ackmate_ack" and run ln -s /usr/local/bin/ag "~/Library/Application Support/TextMate/PlugIns/AckMate.tmplugin/Contents/Resources/ackmate_ack"

Other stuff you might like

• Ack - Better than grep. Without Ack, Ag would not exist.
• AckMate - An ack-powered replacement for TextMate's slow built-in search.
• ack.vim
• ag.vim
• Exuberant Ctags - Faster than Ag, but it builds an index beforehand. Good for really big codebases.
• Git-grep - As fast as Ag but only works on git repos.
• Sack - A utility that wraps Ack and Ag. It removes a lot of repetition from searching and opening matching files.