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
- It ignores file patterns from your
- If there are files in your source repo you don't want to search, just add their patterns to a
.agignorefile. (*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.
brew install the_silver_searcher
port install the_silver_searcher
Ubuntu >= 13.10 (Saucy) or Debian >= 8 (Jessie)
apt-get install silversearcher-ag
yum install the_silver_searcher
rpm -Uvh http://download.fedoraproject.org/pub/epel/7/x86_64/e/epel-release-7-5.noarch.rpm yum install the_silver_searcher
pacman -S the_silver_searcher
sbopkg -i the_silver_searcher
pkg install the_silver_searcher
Building from source
Install dependencies (Automake, pkg-config, PCRE, LZMA):
brew install automake pkg-config pcre xz
port install automake pkgconfig pcre xz
apt-get install -y automake pkg-config libpcre3-dev zlib1g-dev liblzma-dev
yum -y install pkgconfig automake gcc zlib-devel pcre-devel xz-devel
yum -y groupinstall "Development Tools" yum -y install pcre-devel xz-devel
- Windows: It's complicated. See this wiki page.
Run the build script (which just runs aclocal, automake, etc):
mingw32-make -f Makefile.w32
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.
You can use Ag with ack.vim by adding the following line to your
let g:ackprg = 'ag --nogroup --nocolor --column'
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
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.
- 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.