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: 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. 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. ack only searches through files of types that it recognizes. If it can't tell what type a file is, then it won't look. If that's annoying to you, use grep. If you truly want to search every file and every directory, ack won't do it. You'll need to rely on grep. Operate on all files, regardless of type (but still skip directories like blib, CVS, etc.) Print NUM lines of trailing context after matching lines. Print NUM lines of leading context before matching lines. Print NUM lines (default 2) of context around matching lines. Suppress normal output; instead print a count of matching lines for each input file. If -l is in effect, it will only show the number of lines for each file that has lines matching. Without -l, some line counts may be zeroes. --color highlights the matching text. --nocolor supresses the color. This is on by default unless the output is redirected, or running under Windows. Only print the files that would be searched, without actually doing any searching. PATTERN must not be specified, or it will be taken as a path to search. Follow or don't follow symlinks, other than whatever starting files or directories were specified on the command line. This is off by default. Same as -f, but only print files that match REGEX. The entire path and filename are matched against REGEX, and REGEX is a Perl regular expression, not a shell glob. --group groups matches by file name with. This is the default when used interactively. --nogroup prints one result per line, like grep. This is the default when output is redirected. Print the filename for each match. Suppress the prefixing of filenames on output when multiple files are searched. Print a short help statement. Ignore case in the search strings. Only print line NUM of each file. Multiple lines can be given with multiple --line options or as a comma separated list (--line=3,5,7). --line=4-7 also works. The lines are always output in ascending order, no matter the order given on the command line. Only print the filenames of matching files, instead of the matching text. Stop reading a file after NUM matches. Print this manual page. No descending into subdirectories. Show only the part of each line matching PATTERN (turns off text highlighting) Output the evaluation of expr for each line (turns off text highlighting) Prints all lines, whether or not they match the expression. Highlighting will still work, though, so it can be used to highlight matches while still seeing the entire file, as in: # Watch a log file, and highlight a certain IP address $ tail -f ~/access.log | ack --passthru 123.45.67.89 Only works in conjunction with -f, -g, -l or -c (filename output). The filenames are output separated with a null byte instead of the usual newline. This is helpful when dealing with filenames that contain whitespace, e.g. # remove all files of type html ack -f --html --print0 | xargs -0 rm -f Quote all metacharacters. PATTERN is treated as a literal. Specify a path to an alternate .ackrc file. Sorts the found files lexically. Use this if you want your file listings to be deterministic between runs of ack. Display the all-important Bill The Cat logo. Note that the exact spelling of --thpppppt is not important. It's checked against a regular expression. Specify the types of files to include or exclude from a search. TYPE is a filetype, like perl or xml. --type=perl can also be specified as --perl, and --type=noperl can be done as --noperl. 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. All files and directories (including blib/, core.*, ...) are searched, nothing is skipped. Invert match: select non-matching lines Display version and copyright information. Force PATTERN to match only whole words. The PATTERN is wrapped with "\b" metacharacters. Stops after reporting first match of any kind. This is different from --max-count=1 or -m1, where only one match per file is shown. Also, -1 works with -f and -g, where -m does not. 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 filter --color ack looks in your home directory for the .ackrc. You can specify another location with the ACKRC variable, below. Specifies the location of the .ackrc file. If this file doesn't exist, ack looks in the default location. This variable specifies default options to be placed in front of any explicit options on the command line. Specifies the color of the filename when it's printed in --group mode. By default, it's "bold green". 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. Specifies the color of the matching text when printed in --color mode. By default, it's "black on_yellow". See ACK_COLOR_FILENAME for the color specifications.

Vim integration
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 Note that FILES must still match valid selection rules. For example, ack something --perl foo.rb will search nothing, because foo.rb is a Ruby file. Andy Lester, "<andy at petdance.com>" Please report any bugs or feature requests to the issues list at Google Code: <http://code.google.com/p/ack/issues/list> 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. There is a list of enhancements I want to make to ack in the ack issues list at Google Code: <http://code.google.com/p/ack/issues/list> Yes, we want to be able to specify our own filetypes, so you can say .snork files are recognized as Java, or whatever. Patches are always welcome, but patches with tests get the most attention. Support for and information about ack can be found at: <http://petdance.com/ack/> <http://code.google.com/p/ack/issues/list> <http://annocpan.org/dist/ack> <http://cpanratings.perl.org/d/ack> <http://search.cpan.org/dist/ack> <http://ack.googlecode.com/svn/> How appropriate to have acknowledgements! Thanks to everyone who has contributed to ack in any way, including Jason Porritt, Jjgod Jiang, Thomas Klausner, Uri Guttman, Peter Lewis, Kevin Riggle, Ori Avtalion, Torsten Blix, Nigel Metheringham, Gabor Szabo, 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 Rezić, Mark Stosberg, David Alan Pisoni, Adriano Ferreira, James Keenan, Leland Johnson, Ricardo Signes and Pete Krawczyk. Copyright 2005-2007 Andy Lester, all rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.