Usually, I use the grep command/egrep command for code searching on my box. Recently, I come across another cool tool called ag. It is an attempt to make something better than ack, which itself is better than grep command. Let us see how to install and use the ag tool on Unix-like operating systems.
The ag command can recursively search for PATTERN in PATH. Like grep or ack, but faster.
Why use ag tool?
- It is faster than both grep and ack.
- It ignores file patterns found in your ~/.gitignore and ~/.hgignore.
- You can add custom ignore patterns to a ~/.ignore file.
- Ag uses Pthreads to take advantage of multiple CPU cores and search files in parallel.
How to install ag to supercharge string search through a directory
You can install ag as per the version of your Linux distro or Unix variant. Open the Terminal application and type the following command.
Install ag on on a Ubuntu/Debian Linux
Type the following apt command/apt-get command:
$ sudo apt install silversearcher-ag
Sample outputs:
[sudo] password for vivek: Reading package lists... Done Building dependency tree Reading state information... Done The following NEW packages will be installed: silversearcher-ag 0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded. Need to get 37.3 kB of archives. After this operation, 120 kB of additional disk space will be used. Get:1 http://in.archive.ubuntu.com/ubuntu artful/universe amd64 silversearcher-ag amd64 2.0.0-1 [37.3 kB] Fetched 37.3 kB in 1s (22.3 kB/s) Selecting previously unselected package silversearcher-ag. (Reading database ... 196028 files and directories currently installed.) Preparing to unpack .../silversearcher-ag_2.0.0-1_amd64.deb ... Unpacking silversearcher-ag (2.0.0-1) ... Setting up silversearcher-ag (2.0.0-1) ... Processing triggers for man-db (2.7.6.1-2) ...
Install ag on on a RHEL/CentOS 7 or Fedora Linux
First enable the EPEL repo and type the following yum command:
$ sudo yum install the_silver_searcher
Sample outputs:
Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile * base: centos.excellmedia.net * epel: mirror.nes.co.id * extras: mirrors.vinahost.vn * updates: mirrors.vonline.vn Resolving Dependencies --> Running transaction check ---> Package the_silver_searcher.x86_64 0:2.0.0-1.el7 will be installed --> Finished Dependency Resolution Dependencies Resolved =============================================================================== Package Arch Version Repository Size =============================================================================== Installing: the_silver_searcher x86_64 2.0.0-1.el7 epel 48 k Transaction Summary =============================================================================== Install 1 Package Total download size: 48 k Installed size: 104 k Is this ok [y/d/N]: y Downloading packages: the_silver_searcher-2.0.0-1.el7.x86_64.rpm | 48 kB 00:01 Running transaction check Running transaction test Transaction test succeeded Running transaction Installing : the_silver_searcher-2.0.0-1.el7.x86_64 1/1 Verifying : the_silver_searcher-2.0.0-1.el7.x86_64 1/1 Installed: the_silver_searcher.x86_64 0:2.0.0-1.el7 Complete!
Fedora Linux user type the following dnf command:
$ sudo dnf install the_silver_searcher
Install ag on an OpenSUSE Linux
Type the following zypper command:
# zypper install the_silver_searcher
Install ag on an OpenBSD
Type the following pkg_add command:
# pkg_add the_silver_searcher
Install ag on a FreeBSD
Type the following pkg command:
# pkg install the_silver_searcher
Install ag on a macOS Unix
First, install Homebrew on macOS and then type the following brew command:
$ brew install the_silver_searcher
OR use the port command:
$ port install the_silver_searcher
ag syntax
ag’s basic syntax is
ag [option(s)] pattern files
ag [option(s)] pattern file1 file2
ag [option(s)] pattern dir/
Examples
ag can search any number of files simultaneously. Thus, for example, the following would search the three files foo, bar and foobar for any line that contains the string UNIX:
$ ag UNIX foo bar foobar
Sample outputs:
Fig.01: ag command in action
$ ag 'UNIX os' file1 foo barYou can instructs ag to ignore case:
$ ag -i unix dir
$ ag -i unix .
$ ag -i unix foo bar foobar
foo 1:FreeBSD is a better unix 2:No macOS is Unix 5:UNIX 6:ios is UNIX too :P bar 2:UNIX no good for me 5:OpenBSD as a Unix for me foobar 2:I love unix 3:UNIX <3
ag can only report the number of times that the pattern has been matched for each file. Just pass the -c option:
$ ag -i -c unix foo bar foobar
foobar:2
foo:4
bar:2
The search can be restricted to certain types of files. Example:
$ ag --shell 'word' ~/path/
$ ag --shell 'curl' ~/bin/
Above searches for ‘curl’ in files with suffix .sh, .bash, .csh, .tcsh, .ksh, .zsh and .fish shell scripts only. No need to use the find command and grep it. For a list of supported file types run:
$ ag --list-file-types
$ ag --list-file-types | ag -A 'python'
One can search contents of compressed files too. Just pass the -z option:
$ ag -z 'main()' file.zip xkcd.tar.gz
No need to use the egrep command:
$ ag 'regex' path
$ ag '[Cu]url' ~/bin/
To see all help option, type:
$ man ag
$ ag --help
Sample outputs:
Usage: ag [FILE-TYPE] [OPTIONS] PATTERN [PATH] Output Options: --ackmate Print results in AckMate-parseable format -A --after [LINES] Print lines after match (Default: 2) -B --before [LINES] Print lines before match (Default: 2) --[no]break Print newlines between matches in different files (Enabled by default) -c --count Only print the number of matches in each file. (This often differs from the number of matching lines) --[no]color Print color codes in results (Enabled by default) --color-line-number Color codes for line numbers (Default: 1;33) --color-match Color codes for result match numbers (Default: 30;43) --color-path Color codes for path names (Default: 1;32) --column Print column numbers in results --[no]filename Print file names (Enabled unless searching a single file) -H --[no]heading Print file names before each file's matches (Enabled by default) -C --context [LINES] Print lines before and after matches (Default: 2) --[no]group Same as --[no]break --[no]heading -g --filename-pattern PATTERN Print filenames matching PATTERN -l --files-with-matches Only print filenames that contain matches (don't print the matching lines) -L --files-without-matches Only print filenames that don't contain matches --print-all-files Print headings for all files searched, even those that don't contain matches --[no]numbers Print line numbers. Default is to omit line numbers when searching streams -o --only-matching Prints only the matching part of the lines --print-long-lines Print matches on very long lines (Default: >2k characters) --passthrough When searching a stream, print all lines even if they don't match --silent Suppress all log messages, including errors --stats Print stats (files scanned, time taken, etc.) --stats-only Print stats and nothing else. (Same as --count when searching a single file) --vimgrep Print results like vim's :vimgrep /pattern/g would (it reports every match on the line) -0 --null --print0 Separate filenames with null (for 'xargs -0') Search Options: -a --all-types Search all files (doesn't include hidden files or patterns from ignore files) -D --debug Ridiculous debugging (probably not useful) --depth NUM Search up to NUM directories deep (Default: 25) -f --follow Follow symlinks -F --fixed-strings Alias for --literal for compatibility with grep -G --file-search-regex PATTERN Limit search to filenames matching PATTERN --hidden Search hidden files (obeys .*ignore files) -i --ignore-case Match case insensitively --ignore PATTERN Ignore files/directories matching PATTERN (literal file/directory names also allowed) --ignore-dir NAME Alias for --ignore for compatibility with ack. -m --max-count NUM Skip the rest of a file after NUM matches (Default: 10,000) --one-device Don't follow links to other devices. -p --path-to-ignore STRING Use .ignore file at STRING -Q --literal Don't parse PATTERN as a regular expression -s --case-sensitive Match case sensitively -S --smart-case Match case insensitively unless PATTERN contains uppercase characters (Enabled by default) --search-binary Search binary files for matches -t --all-text Search all text files (doesn't include hidden files) -u --unrestricted Search all files (ignore .ignore, .gitignore, etc.; searches binary and hidden files as well) -U --skip-vcs-ignores Ignore VCS ignore files (.gitignore, .hgignore; still obey .ignore) -v --invert-match -w --word-regexp Only match whole words -W --width NUM Truncate match lines after NUM characters -z --search-zip Search contents of compressed (e.g., gzip) files
The silver searcher speed
According to project code:
- 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.
Conclusion
The ag comes with saner defaults than grep and easy to type. However, I will not install it on my server. It might be a good choice for your laptop or desktop computer dedicated to software development. ag was originally created by Geoff Greer. More information (and the latest release) can be found at https://geoff.greer.fm/ag.
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I went looking in the Archlinux repos for the Silver Searcher (aka ag) ;-). Apparently there are some very interesting alternatives. rg (RipGrep) is one of the most interesting and very fast, maybe even faster than ag.
There are also a couple of forks of Silver Searcher, namely The Platinum Searcher and Aswild’s Silver Searcher fork. RipGrep does look good, though. I’m going to install it when I get home.
+1 for ripgrep (rg)
Thank you. I’ve been looking for a tool like this, plus it’s much faster than ack.
Something seems to be missing – the speed comparison tests.
Thanks for this useful tip. Though it might be a YMMV topic, I found the platinum searcher (https://github.com/monochromegane/the_platinum_searcher) pretty good, too. It also has support for codings other than UTF8.
Can you go into mire detail why you won’t be installing it in your server?