| ack - grep-like text finder |
ack - grep-like text finder
ack [options] PATTERN [FILE...]
ack -f [options] [DIRECTORY...]
Ack is designed as a replacement for 99% of the uses of grep.
Ack searches the named input FILEs (or standard input if no files are named, or the file name - is given) for lines containing a match to the given PATTERN. By default, ack prints the matching lines.
Ack can also list files that would be searched, without actually searching them, to let you take advantage of ack's file-type filtering capabilities.
ack is intelligent about the files it searches. It knows about certain file types, based on both the extension on the file and, in some cases, the contents of the file. These selections can be made with the --type option.
With no file selections, ack only searches files of types that it recognizes. If you have a file called foo.wango, and ack doesn't know what a .wango file is, ack won't search it.
The -a option tells ack to select all files, regardless of type.
Some files will never be selected by ack, even with -a, including:
However, ack always searches the files given on the command line, no matter what type. Furthermore, by specifying the -u option all files will be searched.
ack descends through the directory tree of the starting directories specified. However, it will ignore the shadow directories used by many version control systems, and the build directories used by the Perl MakeMaker system. You may add or remove a directory from this list with the --[no]ignore-dir option. The option may be repeated to add/remove multiple directories from the ignore list.
For a complete list of directories that do not get searched, run ack --help.
ack trumps grep as an everyday tool 99% of the time, but don't throw grep away, because there are times you'll still need it.
E.g., searching through huge files looking for regexes that can be expressed with grep syntax should be quicker with grep.
If your script or parent program uses grep --quiet or
--silent or needs exit 2 on IO error, use grep.
On Windows, this option is off by default unless the
the Win32::Console::ANSI manpage module is installed or the ACK_PAGER_COLOR
environment variable is used.
This is off by default.
The options -i, -w, -v, and -Q do not apply to this REGEX.
The options -i, -w, -v, and -Q do not apply to this REGEX.
--nogroup prints one result per line, like grep. This is the default when output is redirected.
This applies only to the PATTERN, not to the regexes given for the -g and -G options.
# search for foo and bar in given files
ack file1 t/file* --match foo
ack file1 t/file* --match bar
ACK_PAGER and ACK_PAGER_COLOR environment variables.
Using --pager does not suppress grouping and coloring like piping output on the command-line does.
# Watch a log file, and highlight a certain IP address
$ tail -f ~/access.log | ack --passthru 123.45.67.89
# remove all files of type html
ack -f --html --print0 | xargs -0 rm -f
This applies only to the PATTERN, not to the regexes given for the -g and -G options.
smartcase in vim. This option is
off by default.
-i always overrides this option.
This applies only to the PATTERN, not to the regexes given for the -g and -G options.
If a file is of both type ``foo'' and ``bar'', specifying --foo and --nobar will exclude the file, because an exclusion takes precedence over an inclusion.
Type specifications can be repeated and are ORed together.
See ack --help=types for a list of valid types.
EXTENSION(s) are recognized as being of (the
existing) type TYPE. See also Defining your own types.
EXTENSION(s) are recognized as being of type
TYPE. This replaces an existing definition for type TYPE. See also
Defining your own types.
This applies only to the PATTERN, not to the regexes given for the -g and -G options.
\b metacharacters.
This applies only to the PATTERN, not to the regexes given for the -g and -G options.
The .ackrc file contains command-line options that are prepended to the command line before processing. Multiple options may live on multiple lines. Lines beginning with a # are ignored. A .ackrc might look like this:
# Always sort the files
--sort-files
# Always color, even if piping to a another program
--color
# Use "less -r" as my pager
--pager=less -r
Note that arguments with spaces in them do not need to be quoted,
as they are not interpreted by the shell. Basically, each line
in the .ackrc file is interpreted as one element of @ARGV.
ack looks in your home directory for the .ackrc. You can specify another location with the ACKRC variable, below.
If --noenv is specified on the command line, the .ackrc file is ignored.
ack allows you to define your own types in addition to the predefined types. This is done with command line options that are best put into an .ackrc file - then you do not have to define your types over and over again. In the following examples the options will always be shown on one command line so that they can be easily copy & pasted.
ack --perl foo searches for foo in all perl files. ack --help=types tells you, that perl files are files ending in .pl, .pm, .pod or .t. So what if you would like to include .xs files as well when searching for --perl files? ack --type-add perl=.xs --perl foo does this for you. --type-add appends additional extensions to an existing type.
If you want to define a new type, or completely redefine an existing type, then use --type-set. ack --type-set eiffel=.e,.eiffel defines the type eiffel to include files with the extensions .e or .eiffel. So to search for all eiffel files containing the word Bertrand use ack --type-set eiffel=.e,.eiffel --eiffel Bertrand. As usual, you can also write --type=eiffel instead of --eiffel. Negation also works, so --noeiffel excludes all eiffel files from a search. Redefining also works: ack --type-set cc=.c,.h and .xs files no longer belong to the type cc.
When defining your own types in the .ackrc file you have to use the following:
--type-set=eiffel=.e,.eiffel
or writing on separate lines
--type-set eiffel=.e,.eiffel
The following does NOT work in the .ackrc file:
--type-set eiffel=.e,.eiffel
In order to see all currently defined types, use --help types, e.g. ack --type-set backup=.bak --type-add perl=.perl --help types
Restrictions:
For commonly-used ack options, environment variables can make life much easier. These variables are ignored if --noenv is specified on the command line.
The recognized attributes are clear, reset, dark, bold, underline, underscore, blink, reverse, concealed black, red, green, yellow, blue, magenta, on_black, on_red, on_green, on_yellow, on_blue, on_magenta, on_cyan, and on_white. Case is not significant. Underline and underscore are equivalent, as are clear and reset. The color alone sets the foreground color, and on_color sets the background color.
This option can also be set with --color-filename.
This option can also be set with --color-match.
See ACK_COLOR_FILENAME for the color specifications.
more, less or most, to which
ack will send its output.
Using ACK_PAGER does not suppress grouping and coloring like
piping output on the command-line does, except that on Windows
ack will assume that ACK_PAGER does not support color.
ACK_PAGER_COLOR overrides ACK_PAGER if both are specified.
ACK_PAGER_COLOR does not suppress grouping and coloring
like piping output on the command-line does.
If you are not on Windows, you never need to use ACK_PAGER_COLOR.
ack integrates easily with the Vim text editor. Set this in your .vimrc to use ack instead of grep:
set grepprg=ack\ -a
That examples uses -a to search through all files, but you may
use other default flags. Now you can search with ack and easily
step through the results in Vim:
:grep Dumper perllib
Phil Jackson put together an ack.el extension that ``provides a simple compilation mode ... has the ability to guess what files you want to search for based on the major-mode.''
http://www.shellarchive.co.uk/content/emacs.html
Pedro Melo is a TextMate user who writes ``I spend my day mostly inside TextMate, and the built-in find-in-project sucks with large projects. So I hacked a TextMate command that was using find + grep to use ack. The result is the Search in Project with ack, and you can find it here: http://www.simplicidade.org/notes/archives/2008/03/search_in_proje.html''
For greater compatibility with grep, ack in normal use returns shell return or exit code of 0 only if something is found and 1 if no match is found.
(Shell exit code 1 is $?=256 in perl with system or backticks.)
The grep code 2 for errors is not used.
If -f or -g are specified, then 0 is returned if at least one
file is found. If no files are found, then 1 is returned.
If ack gives you output you're not expecting, start with a few simple steps.
Your environment variables and .ackrc may be doing things you're not expecting, or forgotten you specified. Use --noenv to ignore your environment and .ackrc.
The reason I created -f in the first place was as a debugging tool. If ack is not finding matches you think it should find, run ack -f to see what files are being checked.
The .ackrc is the place to put all your options you use most of the time but don't want to remember. Put all your --type-add and --type-set definitions in it. If you like --smart-case, set it there, too. I also set --sort-files there.
Ack does more than search files. ack -f --perl will create a
list of all the Perl files in a tree, ideal for sending into xargs.
For example:
# Change all "this" to "that" in all Perl files in a tree.
ack -f --perl | xargs perl -p -i -e's/this/that/g'
or if you prefer:
perl -p -i -e's/this/thatg/' $(ack -f --perl)
If you're searching for something with a regular expression metacharacter, most often a period in a filename or IP address, add the -Q to avoid false positives without all the backslashing. See the following example for more...
Here's one I used the other day to find trouble spots for a website visitor. The user had a problem loading troublesome.gif, so I took the access log and scanned it with ack twice.
ack -Q aa.bb.cc.dd /path/to/access.log | ack -Q -B5 troublesome.gif
The first ack finds only the lines in the Apache log for the given IP. The second finds the match on my troublesome GIF, and shows the previous five lines from the log in each case.
Join the ack-users mailing list. Send me your tips and I may add them here.
Probably because it's of a type that ack doesn't recognize.
ack's searching behavior is driven by filetype. If ack doesn't know what kind of file it is, ack ignores it.
If you want ack to search files that it doesn't recognize, use the
-a switch.
If you want ack to search every file, even ones that it always
ignores like coredumps and backup files, use the -u switch.
ack is designed by a programmer, for programmers, for searching large trees of code. Most codebases have a lot files in them which aren't source files (like compiled object files, source control metadata, etc), and grep wastes a lot of time searching through all of those as well and returning matches from those files.
That's why ack's behavior of not searching things it doesn't recognize is one of its greatest strengths: the speed you get from only searching the things that you want to be looking at.
No, ack will always be read-only. Perl has a perfectly good way
to do search & replace in files, using the -i, -p and -n
switches.
You can certainly use ack to select your files to update. For example, to change all ``foo'' to ``bar'' in all PHP files, you can do this form the Unix shell:
$ perl -i -p -e's/foo/bar/g' $(ack -f --php)
That's an enhancement. Please see the section in the manual about enhancements.
Yes, I know.
The name of the program is ``ack''. Some packagers have called it ``ack-grep'' when creating packages because there's already a package out there called ``ack'' that has nothing to do with this ack.
I suggest you rename your ack-grep install to ``ack'' because one of the crucial benefits of ack is having a name that's so short and simple to type.
Andy Lester, <andy at petdance.com>
Please report any bugs or feature requests to the issues list at Github: http://github.com/petdance/ack/issues
All enhancement requests MUST first be posted to the ack-users mailing list at http://groups.google.com/group/ack-users. I will not consider a request without it first getting seen by other ack users. This includes requests for new filetypes.
There is a list of enhancements I want to make to ack in the ack issues list at Github: http://github.com/petdance/ack/issues
Patches are always welcome, but patches with tests get the most attention.
Support for and information about ack can be found at:
How appropriate to have acknowledgements!
Thanks to everyone who has contributed to ack in any way, including Packy Anderson, JR Boyens, Dan Sully, Ryan Niebur, Kent Fredric, Mike Morearty, Ingmar Vanhassel, Eric Van Dewoestine, Sitaram Chamarty, Adam James, Richard Carlsson, Pedro Melo, AJ Schuster, Phil Jackson, Michael Schwern, Jan Dubois, Christopher J. Madsen, Matthew Wickline, David Dyck, Jason Porritt, Jjgod Jiang, Thomas Klausner, Uri Guttman, Peter Lewis, Kevin Riggle, Ori Avtalion, Torsten Blix, Nigel Metheringham, Gábor Szabó, Tod Hagan, Michael Hendricks, Ævar Arnfjörð Bjarmason, Piers Cawley, Stephen Steneker, Elias Lutfallah, Mark Leighton Fisher, Matt Diephouse, Christian Jaeger, Bill Sully, Bill Ricker, David Golden, Nilson Santos F. Jr, Elliot Shank, Merijn Broeren, Uwe Voelker, Rick Scott, Ask Bjørn Hansen, Jerry Gay, Will Coleda, Mike O'Regan, Slaven Rezi&0x107;, Mark Stosberg, David Alan Pisoni, Adriano Ferreira, James Keenan, Leland Johnson, Ricardo Signes and Pete Krawczyk.
Copyright 2005-2009 Andy Lester.
This program is free software; you can redistribute it and/or modify it under the terms of either:
| ack - grep-like text finder |