NAME¶
ack-grep - grep-like text finder
SYNOPSIS¶
ack-grep [options] PATTERN [FILE...]
ack-grep -f [options] [DIRECTORY...]
DESCRIPTION¶
Ack-Grep is designed as a replacement for 99% of the uses of
grep.
Ack-Grep searches the named input FILEs (or standard input, if it is a pipe
instead of a terminal) for lines containing a match to the given PATTERN. If
no files are named, the current directory is searched. By default, ack-grep
prints the matching lines.
Ack-Grep can also list files that would be searched, without actually searching
them, to let you take advantage of ack-grep's file-type filtering
capabilities.
FILE SELECTION¶
ack-grep 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-grep only searches files of types that it
recognizes. If you have a file called
foo.wango, and
ack-grep
doesn't know what a .wango file is,
ack-grep won't search it.
The
-a option tells
ack-grep to select all files, regardless of
type.
Some files will never be selected by
ack-grep, even with
-a,
including:
- •
- Backup files: Files matching #*# or ending with
~.
- •
- Coredumps: Files matching core.\d+
However,
ack-grep always searches the files given on the command line, no
matter what type. Furthermore, by specifying the
-u option all files
will be searched.
DIRECTORY SELECTION¶
ack-grep 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-grep
--help.
WHEN TO USE GREP¶
ack-grep 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.
OPTIONS¶
- -a, --all
- Operate on all files, regardless of type (but still skip
directories like blib, CVS, etc.)
- -A NUM,
--after-context=NUM
- Print NUM lines of trailing context after matching
lines.
- -B NUM,
--before-context= NUM
- Print NUM lines of leading context before matching
lines.
- -C [NUM],
--context[=NUM]
- Print NUM lines (default 2) of context around
matching lines.
- -c, --count
- 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.
If combined with -h (--no-filename) ack-grep outputs only one
total count.
- --color, --nocolor
- --color highlights the matching text.
--nocolor supresses the color. This is on by default unless the
output is redirected.
On Windows, this option is off by default unless the Win32::Console::ANSI
module is installed or the "ACK_PAGER_COLOR" environment
variable is used.
- --color-filename=color
- Sets the color to be used for filenames.
- --color-match=color
- Sets the color to be used for matches.
- --color-lineno=color
- Sets the color to be used for line numbers.
- --column
- Show the column number of the first match. This is helpful
for editors that can place your cursor at a given position.
- --env, --noenv
- --noenv disables all environment processing. No
.ackrc is read and all environment variables are ignored. By
default, ack-grep considers .ackrc and settings in the
environment.
- --flush
- --flush flushes output immediately. This is off by
default unless ack-grep is running interactively (when output goes to a
pipe or file).
- -f
- 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, --nofollow
- Follow or don't follow symlinks, other than whatever
starting files or directories were specified on the command line.
This is off by default.
- -G REGEX
- Only paths matching REGEX are included in the
search. The entire path and filename are matched against REGEX, and
REGEX is a Perl regular expression, not a shell glob.
The options -i, -w, -v, and -Q do not apply to
this REGEX.
- -g REGEX
- Print files where the relative path + filename matches
REGEX. This option is a convenience shortcut for -f -G
REGEX.
The options -i, -w, -v, and -Q do not apply to
this REGEX.
- --group, --nogroup
- --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.
- -H, --with-filename
- Print the filename for each match.
- -h, --no-filename
- Suppress the prefixing of filenames on output when multiple
files are searched.
- --help
- Print a short help statement.
- -i, --ignore-case
- Ignore case in the search strings.
This applies only to the PATTERN, not to the regexes given for the -g
and -G options.
- --[no]ignore-dir=DIRNAME
- Ignore directory (as CVS, .svn, etc are ignored). May be
used multiple times to ignore multiple directories. For example, mason
users may wish to include --ignore-dir=data. The
--noignore-dir option allows users to search directories which
would normally be ignored (perhaps to research the contents of
.svn/props directories).
The DIRNAME must always be a simple directory name. Nested
directories like foo/bar are NOT supported. You would need to
specify --ignore-dir=foo and then no files from any foo directory
are taken into account by ack-grep unless given explicitly on the command
line.
- --line=NUM
- 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.
- -l, --files-with-matches
- Only print the filenames of matching files, instead of the
matching text.
- -L, --files-without-matches
- Only print the filenames of files that do NOT match.
This is equivalent to specifying -l and -v.
- --match REGEX
- Specify the REGEX explicitly. This is helpful if you
don't want to put the regex as your first argument, e.g. when executing
multiple searches over the same set of files.
# search for foo and bar in given files
ack-grep file1 t/file* --match foo
ack-grep file1 t/file* --match bar
- -m=NUM,
--max-count=NUM
- Stop reading a file after NUM matches.
- --man
- Print this manual page.
- -n, --no-recurse
- No descending into subdirectories.
- -o
- Show only the part of each line matching PATTERN (turns off
text highlighting)
- --output=expr
- Output the evaluation of expr for each line (turns
off text highlighting)
- --pager=program
- Direct ack-grep's output through program. This can
also be specified via the "ACK_PAGER" and
"ACK_PAGER_COLOR" environment variables.
Using --pager does not suppress grouping and coloring like piping output on
the command-line does.
- --passthru
- 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-grep --passthru 123.45.67.89
- --print0
- 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-grep -f --html --print0 | xargs -0 rm -f
- -Q, --literal
- Quote all metacharacters in PATTERN, it is treated as a
literal.
This applies only to the PATTERN, not to the regexes given for the -g
and -G options.
- -r, -R, --recurse
- Recurse into sub-directories. This is the default and just
here for compatibility with grep. You can also use it for turning
--no-recurse off.
- --smart-case, --no-smart-case
- Ignore case in the search strings if PATTERN contains no
uppercase characters. This is similar to "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.
- --sort-files
- Sorts the found files lexically. Use this if you want your
file listings to be deterministic between runs of ack-grep.
- --show-types
- Outputs the filetypes that ack-grep associates with each
file.
Works with -f and -g options.
- --thpppt
- 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.
- --type=TYPE, --type=noTYPE
- 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-grep --help=types for a list of valid types.
- --type-add
TYPE=.EXTENSION
[,.EXT2 [,...]]
- Files with the given EXTENSION(s) are recognized as being
of (the existing) type TYPE. See also "Defining your own
types".
- --type-set
TYPE=.EXTENSION
[,.EXT2 [,...]]
- Files with the given EXTENSION(s) are recognized as being
of type TYPE. This replaces an existing definition for type TYPE. See also
"Defining your own types".
- -u, --unrestricted
- All files and directories (including blib/, core.*, ...)
are searched, nothing is skipped. When both -u and
--ignore-dir are used, the --ignore-dir option has no
effect.
- -v, --invert-match
- Invert match: select non-matching lines
This applies only to the PATTERN, not to the regexes given for the -g
and -G options.
- --version
- Display version and copyright information.
- -w, --word-regexp
- Force PATTERN to match only whole words. The PATTERN is
wrapped with "\b" metacharacters.
This applies only to the PATTERN, not to the regexes given for the -g
and -G options.
- -1
- 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¶
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-grep 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.
Defining your own types¶
ack-grep 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-grep --perl foo searches for foo in all perl files.
ack-grep
--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-grep --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-grep --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-grep --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-grep --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-grep --type-set backup=.bak --type-add perl=.perl --help types
Restrictions:
- •
- The types 'skipped', 'make', 'binary' and 'text' are
considered "builtin" and cannot be altered.
- •
- The shebang line recognition of the types 'perl', 'ruby',
'php', 'python', 'shell' and 'xml' cannot be redefined by
--type-set, it is always active. However, the shebang line is only
examined for files where the extension is not recognised. Therefore it is
possible to say ack-grep --type-set perl=.perl --type-set
foo=.pl,.pm,.pod,.t --perl --nofoo and only find your shiny new
.perl files (and all files with unrecognized extension and perl on
the shebang line).
ENVIRONMENT VARIABLES¶
For commonly-used ack-grep options, environment variables can make life much
easier. These variables are ignored if
--noenv is specified on the
command line.
- ACKRC
- Specifies the location of the .ackrc file. If this
file doesn't exist, ack-grep looks in the default location.
- ACK_OPTIONS
- This variable specifies default options to be placed in
front of any explicit options on the command line.
- ACK_COLOR_FILENAME
- 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.
This option can also be set with --color-filename.
- ACK_COLOR_MATCH
- Specifies the color of the matching text when printed in
--color mode. By default, it's "black on_yellow".
This option can also be set with --color-match.
See ACK_COLOR_FILENAME for the color specifications.
- ACK_COLOR_LINENO
- Specifies the color of the line number when printed in
--color mode. By default, it's "bold yellow".
This option can also be set with --color-lineno.
See ACK_COLOR_FILENAME for the color specifications.
- ACK_PAGER
- Specifies a pager program, such as "more",
"less" or "most", to which ack-grep 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-grep
will assume that "ACK_PAGER" does not support color.
"ACK_PAGER_COLOR" overrides "ACK_PAGER" if both are
specified.
- ACK_PAGER_COLOR
- Specifies a pager program that understands ANSI color
sequences. Using "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".
Vim integration¶
ack-grep integrates easily with the Vim text editor. Set this in your
.vimrc to use
ack-grep instead of
grep:
set grepprg=ack-grep\ -a
That examples uses "-a" to search through all files, but you may use
other default flags. Now you can search with
ack-grep and easily step
through the results in Vim:
:grep Dumper perllib
Emacs integration¶
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>
TextMate integration¶
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-grep. The
result is the Search in Project with ack-grep, and you can find it here:
<
http://www.simplicidade.org/notes/archives/2008/03/search_in_proje.html>"
Shell and Return Code¶
For greater compatibility with
grep,
ack-grep 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.
DEBUGGING ACK-GREP PROBLEMS¶
If ack-grep gives you output you're not expecting, start with a few simple
steps.
Use --noenv¶
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.
Use -f to see what files you're scanning¶
The reason I created
-f in the first place was as a debugging tool. If
ack-grep is not finding matches you think it should find, run
ack-grep
-f to see what files are being checked.
TIPS¶
Use the .ackrc file.¶
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.
Use -f for working with big codesets¶
Ack-Grep does more than search files. "ack-grep -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-grep -f --perl | xargs perl -p -i -e's/this/that/g'
or if you prefer:
perl -p -i -e's/this/thatg/' $(ack-grep -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...
Use ack-grep to watch log files¶
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-grep twice.
ack-grep -Q aa.bb.cc.dd /path/to/access.log | ack-grep -Q -B5 troublesome.gif
The first ack-grep 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.
Share your knowledge¶
Join the ack-users mailing list. Send me your tips and I may add them here.
FAQ¶
Why isn't ack-grep finding a match in (some file)?¶
Probably because it's of a type that ack-grep doesn't recognize. ack-grep's
searching behavior is driven by filetype.
If ack-grep doesn't know
what kind of file it is, ack-grep ignores the file.
Use the "-f" switch to see a list of files that ack-grep will search
for you.
If you want ack-grep to search files that it doesn't recognize, use the
"-a" switch.
If you want ack-grep to search every file, even ones that it always ignores like
coredumps and backup files, use the "-u" switch.
Why does ack-grep ignore unknown files by default?¶
ack-grep 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-grep'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.
Wouldn't it be great if ack-grep did search &
replace?¶
No, ack-grep 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-grep to select your files to update. For example, to
change all "foo" to "bar" in all PHP files, you can do
this from the Unix shell:
$ perl -i -p -e's/foo/bar/g' $(ack-grep -f --php)
Can you make ack-grep recognize .xyz files?¶
That's an enhancement. Please see the section in the manual about enhancements.
There's already a program/package called ack.¶
Yes, I know.
Why is it called ack-grep if it's called ack?¶
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 make a symlink named
ack that points to
ack-grep
because one of the crucial benefits of ack is having a name that's so short
and simple to type.
To do that, run this with
sudo or as root:
ln -s /usr/bin/ack-grep /usr/bin/ack
What does ack mean?¶
Nothing. I wanted a name that was easy to type and that you could pronounce as a
single syllable.
Can I do multi-line regexes?¶
No, ack-grep does not support regexes that match multiple lines. Doing so would
require reading in the entire file at a time.
If you want to see lines near your match, use the "--A",
"--B" and "--C" switches for displaying context.
AUTHOR¶
Andy Lester, "<andy at petdance.com>"
BUGS¶
Please report any bugs or feature requests to the issues list at Github:
<
http://github.com/petdance/ack/issues>
ENHANCEMENTS¶
All enhancement requests MUST first be posted to the ack-users mailing list at
http://groups.google.com/group/ack-users
<
http://groups.google.com/group/ack-users>. I will not consider a
request without it first getting seen by other ack-grep users. This includes
requests for new filetypes.
There is a list of enhancements I want to make to
ack-grep 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¶
Support for and information about
ack-grep can be found at:
- •
- The ack homepage
<http://betterthangrep.com/>
- •
- The ack issues list at Github
<http://github.com/petdance/ack/issues>
- •
- AnnoCPAN: Annotated CPAN documentation
<http://annocpan.org/dist/ack>
- •
- CPAN Ratings
<http://cpanratings.perl.org/d/ack>
- •
- Search CPAN
<http://search.cpan.org/dist/ack>
- •
- Git source repository
<http://github.com/petdance/ack>
ACKNOWLEDGEMENTS¶
How appropriate to have
acknowledgements!
Thanks to everyone who has contributed to ack-grep in any way, including Matthew
Wild, Scott Kyle, Nick Hooey, Bo Borgerson, Mark Szymanski, Marq Schneider,
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, Gabor Szabo, Tod Hagan, Michael
Hendricks, AEvar Arnfjoerd` 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 Bjorn Hansen, Jerry Gay, Will Coleda, Mike
O'Regan, Slaven ReziX, Mark Stosberg, David Alan Pisoni, Adriano Ferreira,
James Keenan, Leland Johnson, Ricardo Signes and Pete Krawczyk.
COPYRIGHT & LICENSE¶
Copyright 2005-2011 Andy Lester.
This program is free software; you can redistribute it and/or modify it under
the terms of the Artistic License v2.0.