grep searches for lines matching a pattern.
This document was produced for version 2.5.1 of GNU
grep.
grep searches the input files
for lines containing a match to a given
pattern list. When it finds a match in a line, it copies the line to standard
output (by default), or does whatever other sort of output you have requested
with options.
Though grep expects to do the matching on text,
it has no limits on input line length other than available memory,
and it can match arbitrary characters within a line.
If the final byte of an input file is not a newline,
grep silently supplies one.
Since newline is also a separator for the list of patterns, there
is no way to match newline characters in a text.
grepgrep comes with a rich set of options from POSIX.2 and GNU
extensions.
-c
--count
-v, --invert-match option,
count non-matching lines.
-e pattern--regexp=pattern-.
-f file--file=file-i
--ignore-case
-l
--files-with-matches
-n
--line-number
-o
--only-matching
-q
--quiet
--silent
-s or --no-messages option.
-s
--no-messages
grep, traditional
grep did not conform to POSIX.2, because traditional
grep lacked a -q option and its -s option behaved
like GNU grep's -q option. Shell scripts intended
to be portable to traditional grep should avoid both
-q and -s and should redirect
output to /dev/null instead.
-v
--invert-match
-x
--line-regexp
-A num--after-context=num-B num--before-context=num-C num--context=num--colour[=WHEN]
--color[=WHEN]
-num--context=num-V
--version
grep to the standard output stream.
This version number should be included in all bug reports.
--help
--binary-files=typebinary, and grep normally outputs either
a one-line message saying that a binary file matches, or no message if
there is no match. If type is without-match,
grep assumes that a binary file does not match;
this is equivalent to the -I option. If type
is text, grep processes a binary file as if it were
text; this is equivalent to the -a option.
Warning: --binary-files=text might output binary garbage,
which can have nasty side effects if the output is a terminal and if the
terminal driver interprets some of it as commands.
-b
--byte-offset
grep runs on MS-DOS or MS-Windows, the printed
byte offsets
depend on whether the -u (--unix-byte-offsets) option is
used; see below.
-D action--devices=actionread, which means that devices are
read just as if they were ordinary files.
If action is skip, devices, FIFOs and sockets are silently
skipped.
-d action--directories=actionread, which means that directories are
read just as if they were ordinary files (some operating systems
and filesystems disallow this, and will cause grep to print error
messages for every directory or silently skip them). If action is
skip, directories are silently skipped. If action is
recurse, grep reads all files under each directory,
recursively; this is equivalent to the -r option.
-H
--with-filename
-h
--no-filename
--line-buffered
--label=LABELgzip -cd foo.gz |grep --label=foo something
-L
--files-without-match
-a
--text
--binary-files=text option.
-I
--binary-files=without-match option.
-w
--word-regexp
-r
-R
--recursive
--directories=recurse option.
--include=file_pattern--exclude=file_pattern-m num--max-count=numgrep ensures that the standard input is positioned to
just after the last matching line before exiting, regardless of the
presence of trailing context lines. This enables a calling process
to resume a search. For example, the following shell script makes use
of it:
while grep -m 1 PATTERN
do
echo xxxx
done < FILE
But the following probably will not work because a pipe is not a regular file:
# This probably will not work.
cat FILE |
while grep -m 1 PATTERN
do
echo xxxx
done
When grep stops after NUM matching lines, it outputs
any trailing context lines. Since context does not include matching
lines, grep will stop when it encounters another matching line.
When the -c or --count option is also used,
grep does not output a count greater than num.
When the -v or --invert-match option is
also used, grep stops after outputting num
non-matching lines.
-y
-i.
-U
--binary
grep guesses the file type by looking
at the contents of the first 32kB read from the file.
If grep decides the file is a text file, it strips the
CR characters from the original file contents (to make
regular expressions with ^ and $ work correctly).
Specifying -U overrules this guesswork, causing all
files to be read and passed to the matching mechanism
verbatim; if the file is a text file with CR/LF pairs
at the end of each line, this will cause some regular
expressions to fail. This option has no effect on platforms other than
MS-DOS and MS-Windows.
-u
--unix-byte-offsets
grep to report byte offsets as if the file were Unix style
text file, i.e., the byte offsets ignore the CR characters which were
stripped. This will produce results identical to running grep on
a Unix machine. This option has no effect unless -b
option is also used; it has no effect on platforms other than MS-DOS and
MS-Windows.
--mmap
mmap system call to read input, instead of
the default read system call. In some situations, --mmap
yields better performance. However, --mmap can cause undefined
behavior (including core dumps) if an input file shrinks while
grep is operating, or if an I/O error occurs.
-Z
--null
NUL character) instead of the
character that normally follows a file name. For example, grep
-lZ outputs a zero byte after each file name instead of the usual
newline. This option makes the output unambiguous, even in the presence
of file names containing unusual characters like newlines. This option
can be used with commands like find -print0, perl -0,
sort -z, and xargs -0 to process arbitrary file names,
even those that contain newline characters.
-z
--null-data
NUL character) instead of a newline. Like the -Z
or --null option, this option can be used with commands like
sort -z to process arbitrary file names.
Several additional options control which variant of the grep
matching engine is used. See Grep Programs.
Grep's behavior is affected by the following environment variables.
A locale LC_foo is specified by examining the three
environment variables LC_ALL, LC_foo, and LANG,
in that order. The first of these variables that is set specifies the
locale. For example, if LC_ALL is not set, but LC_MESSAGES
is set to pt_BR, then Brazilian Portuguese is used for the
LC_MESSAGES locale. The C locale is used if none of these
environment variables are set, or if the locale catalog is not
installed, or if grep was not compiled with national language
support (NLS).
GREP_OPTIONS
GREP_OPTIONS is
--binary-files=without-match --directories=skip, grep
behaves as if the two options --binary-files=without-match and
--directories=skip had been specified before
any explicit options. Option specifications are separated by
whitespace. A backslash escapes the next character, so it can be used to
specify an option containing whitespace or a backslash.
GREP_COLOR
LC_ALL
LC_COLLATE
LANG
LC_COLLATE locale, which determines
the collating sequence used to interpret range expressions like
[a-z].
LC_ALL
LC_CTYPE
LANG
LC_CTYPE locale, which determines the
type of characters, e.g., which characters are whitespace.
LC_ALL
LC_MESSAGES
LANG
LC_MESSAGES locale, which determines
the language that grep uses for messages. The default C
locale uses American English messages.
POSIXLY_CORRECT
grep behaves as POSIX.2 requires; otherwise,
grep behaves more like other GNU programs. POSIX.2
requires that options that
follow file names must be treated as file names; by default, such
options are permuted to the front of the operand list and are treated as
options. Also, POSIX.2 requires that unrecognized options be
diagnosed as
"illegal", but since they are not really against the law the default
is to diagnose them as "invalid". POSIXLY_CORRECT also
disables _N_GNU_nonoption_argv_flags_, described below.
_N_GNU_nonoption_argv_flags_
grep's numeric process ID.) If the
ith character of this environment variable's value is 1, do
not consider the ith operand of grep to be an option, even if
it appears to be one. A shell can put this variable in the environment
for each command it runs, specifying which operands are the results of
file name wildcard expansion and therefore should not be treated as
options. This behavior is available only with the GNU C library, and
only when POSIXLY_CORRECT is not set.
Normally, exit status is 0 if selected lines are found and 1 otherwise.
But the exit status is 2 if an error occurred, unless the -q or
--quiet or --silent option is used and a selected line
is found.
grep programsgrep 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, grep prints the
matching lines. There are four major variants of grep,
controlled by the following options.
-G
--basic-regexp
-E
--extended-regexp
-F
--fixed-strings
-P
--perl-regexp
In addition, two variant programs EGREP and FGREP are available.
EGREP is the same as grep -E. FGREP is the
same as grep -F.
A regular expression is a pattern that describes a set of strings.
Regular expressions are constructed analogously to arithmetic expressions,
by using various operators to combine smaller expressions.
grep understands two different versions of regular expression
syntax: "basic"(BRE) and "extended"(ERE). In GNU grep,
there is no difference in available functionality using either syntax.
In other implementations, basic regular expressions are less powerful.
The following description applies to extended regular expressions;
differences for basic regular expressions are summarized afterwards.
The fundamental building blocks are the regular expressions that match a single character. Most characters, including all letters and digits, are regular expressions that match themselves. Any metacharacter with special meaning may be quoted by preceding it with a backslash.
A regular expression may be followed by one of several repetition operators:
.
. matches any single character.
?
*
+
{n}
{n,}
{n,m}
Two regular expressions may be concatenated; the resulting regular expression matches any string formed by concatenating two substrings that respectively match the concatenated subexpressions.
Two regular expressions may be joined by the infix operator |; the
resulting regular expression matches any string matching either subexpression.
Repetition takes precedence over concatenation, which in turn takes precedence over alternation. A whole subexpression may be enclosed in parentheses to override these precedence rules.
A bracket expression is a list of characters enclosed by [ and
]. It matches any single character in that list; if the first
character of the list is the caret ^, then it matches any character
not in the list. For example, the regular expression
[0123456789] matches any single digit.
Within a bracket expression, a range expression consists of two
characters separated by a hyphen. It matches any single character that
sorts between the two characters, inclusive, using the locale's
collating sequence and character set. For example, in the default C
locale, [a-d] is equivalent to [abcd]. Many locales sort
characters in dictionary order, and in these locales [a-d] is
typically not equivalent to [abcd]; it might be equivalent to
[aBbCcDd], for example. To obtain the traditional interpretation
of bracket expressions, you can use the C locale by setting the
LC_ALL environment variable to the value C.
Finally, certain named classes of characters are predefined within
bracket expressions, as follows.
Their interpretation depends on the LC_CTYPE locale; the
interpretation below is that of the C locale, which is the default
if no LC_CTYPE locale is specified.
[:alnum:]
[:alpha:] and [:digit:].
[:alpha:]
[:lower:] and [:upper:].
[:blank:]
[:cntrl:]
DEL). In other character sets, these are
the equivalent characters, if any.
[:digit:]
0 1 2 3 4 5 6 7 8 9.
[:graph:]
[:alnum:] and [:punct:].
[:lower:]
a b c d e f g h i j k l m n o p q r s t u v w x y z.
[:print:]
[:alnum:], [:punct:], and space.
[:punct:]
! " # $ % & ' ( ) * + , - . / : ; < = > ? @ [ \ ] ^ _ ` { | } ~.
[:space:]
[:upper:]
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z.
[:xdigit:]
0 1 2 3 4 5 6 7 8 9 A B C D E F a b c d e f.
[[:alnum:]] means [0-9A-Za-z], except the latter
depends upon the C locale and the ASCII character
encoding, whereas the former is independent of locale and character set.
(Note that the brackets in these class names are
part of the symbolic names, and must be included in addition to
the brackets delimiting the bracket list.)
Most metacharacters lose their special meaning inside lists.
]
] character a list item, you must put it first.
[.
.]
[=
=]
[:
:]
-
^
^
character a list item, place it anywhere but first.
The \ when followed by certain ordinary characters take a special
meaning :
\b
\B
\<
\>
\w
[[:alnum:]].
\W
[^[:alnum:]].
For example , \brat\b matches the separate word rat,
c\Brat\Be matches crate, but dirty \Brat doesn't
match dirty rat.
The caret ^ and the dollar sign $ are metacharacters that
respectively match the empty string at the beginning and end of a line.
The back-reference \n, where n is a single digit, matches
the substring previously matched by the nth parenthesized subexpression
of the regular expression. For example, (a)\1 matches aa.
When use with alternation if the group does not participate in the match, then
the back-reference makes the whole match fail. For example, a(.)|b\1
will not match ba. When multiple regular expressions are given with
-e or from a file -f file, the back-referecences are local to
each expression.
In basic regular expressions the metacharacters ?, +,
{, |, (, and ) lose their special meaning;
instead use the backslashed versions \?, \+, \{,
\|, \(, and \).
Traditional egrep did not support the { metacharacter,
and some egrep implementations support \{ instead, so
portable scripts should avoid { in egrep patterns and
should use [{] to match a literal {.
GNU egrep attempts to support traditional usage by
assuming that { is not special if it would be the start of an
invalid interval specification. For example, the shell command
egrep '{1' searches for the two-character string {1
instead of reporting a syntax error in the regular expression.
POSIX.2 allows this behavior as an extension, but portable scripts
should avoid it.
Here is an example shell command that invokes GNU grep:
grep -i 'hello.*world' menu.h main.c
This lists all lines in the files menu.h and main.c that
contain the string hello followed by the string world;
this is because .* matches zero or more characters within a line.
See Regular Expressions. The -i option causes grep
to ignore case, causing it to match the line Hello, world!, which
it would not otherwise match. See Invoking, for more details about
how to invoke grep.
Here are some common questions and answers about grep usage.
grep -l 'main' *.c
lists the names of all C files in the current directory whose contents
mention main.
grep -r 'hello' /home/gigi
searches for hello in all files under the directory
/home/gigi. For more control of which files are searched, use
find, grep and xargs. For example,
the following command searches only C files:
find /home/gigi -name '*.c' -print | xargs grep 'hello' /dev/null
This differs from the command:
grep -r 'hello' *.c
which merely looks for hello in all files in the current
directory whose names end in .c. Here the -r is
probably unnecessary, as recursion occurs only in the unlikely event
that one of .c files is a directory.
-?
grep -e '--cut here--' *
searches for all lines matching --cut here--. Without -e,
grep would attempt to parse --cut here-- as a list of
options.
grep -w 'hello' *
searches only for instances of hello that are entire words; it
does not match Othello. For more control, use \< and
\> to match the start and end of words. For example:
grep 'hello\>' *
searches only for words ending in hello, so it matches the word
Othello.
grep -C 2 'hello' *
prints two lines of context around each matching line.
Append /dev/null:
grep 'eli' /etc/passwd /dev/null
gets you:
/etc/passwd:eli:DNGUTF58.IMe.:98:11:Eli Smith:/home/do/eli:/bin/bash
ps output?
ps -ef | grep '[c]ron'
If the pattern had been written without the square brackets, it would
have matched not only the ps output line for cron,
but also the ps output line for grep.
Note that some platforms ps limit the ouput to the width
of the screen, grep does not have any limit on the length of a line
except the available memory.
grep report "Binary file matches"?
If grep listed all matching "lines" from a binary file, it
would probably generate output that is not useful, and it might even
muck up your display. So GNU grep suppresses output from
files that appear to be binary files. To force GNU grep
to output lines even from files that appear to be binary, use the
-a or --binary-files=text option. To eliminate the
"Binary file matches" messages, use the -I or
--binary-files=without-match option.
grep -lv print nonmatching file names?
grep -lv lists the names of all files containing one or more
lines that do not match. To list the names of all files that contain no
matching lines, use the -L or --files-without-match
option.
|, but what about AND?
grep 'paul' /etc/motd | grep 'franc,ois'
finds all lines that contain both paul and franc,ois.
Use the special file name -:
cat /etc/passwd | grep 'alain' - /etc/motd
It can be done by using the back referecences, for example a palindrome of 4 chararcters can be written in BRE.
grep -w -e '\(.\)\(.\).\2\1' file
It matches the word "radar" or "civic".
Guglielmo Bondioni proposed a single RE that finds all the palindromes up to 19 characters long.
egrep -e '^(.?)(.?)(.?)(.?)(.?)(.?)(.?)(.?)(.?).?\9\8\7\6\5\4\3\2\1$' file
Note this is done by using GNU ERE extensions, it might not be portable on other greps.
/bin/echo "ba" | egrep '(a)\1|(b)\1'
The first alternate branch fails then the first group was not in the match this will make the second alternate branch fails. For example, "aaba" will match, the first group participate in the match and can be reuse in the second branch.
grep, fgrep, egrep stand for ?
grep comes from the way line editing was done on Unix. For example,
ed uses this syntax to print a list of matching lines on the screen.
global/regular expression/print
g/re/p
fgrep stands for Fixed grep, egrep Extended
grep.
Email bug reports to bug-grep@gnu.org.
Large repetition counts in the {n,m} construct may cause
grep to use lots of memory. In addition, certain other
obscure regular expressions require exponential time and
space, and may cause grep to run out of memory.
Back-references are very slow, and may require exponential time.
GNU grep is licensed under the GNU GPL, which makes it free software.
Please note that "free" in "free software" refers to liberty, not price. As some GNU project advocates like to point out, think of "free speech" rather than "free beer". The exact and legally binding distribution terms are spelled out below; in short, you have the right (freedom) to run and change grep and distribute it to other people, and even--if you want--charge money for doing either. The important restriction is that you have to grant your recipients the same rights and impose the same restrictions.
This method of licensing software is also known as open source
because, among other things, it makes sure that all recipients will
receive the source code along with the program, and be able to improve
it. The GNU project prefers the term "free software" for reasons
outlined at
<http://www.gnu.org/philosophy/free-software-for-freedom.html>.
The exact license terms are defined by this paragraph and the GNU General Public License it refers to:
GNU grep is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.GNU grep is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
A copy of the GNU General Public License is included as part of this manual; if you did not receive it, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
In addition to this, this manual is free in the same sense:
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation; with the Invariant Sections being "GNU General Public License" and "GNU Free Documentation License", with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License".
The full texts of the GNU General Public License and of the GNU Free Documentation License are available below.
Copyright © 1989, 1991 Free Software Foundation, Inc.
675 Mass Ave, Cambridge, MA 02139, USA
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
The licenses for most software are designed to take away your freedom to share and change it. By contrast, the GNU General Public License is intended to guarantee your freedom to share and change free software--to make sure the software is free for all its users. This General Public License applies to most of the Free Software Foundation's software and to any other program whose authors commit to using it. (Some other Free Software Foundation software is covered by the GNU Library General Public License instead.) You can apply it to your programs, too.
When we speak of free software, we are referring to freedom, not price. Our General Public Licenses are designed to make sure that you have the freedom to distribute copies of free software (and charge for this service if you wish), that you receive source code or can get it if you want it, that you can change the software or use pieces of it in new free programs; and that you know you can do these things.
To protect your rights, we need to make restrictions that forbid anyone to deny you these rights or to ask you to surrender the rights. These restrictions translate to certain responsibilities for you if you distribute copies of the software, or if you modify it.
For example, if you distribute copies of such a program, whether gratis or for a fee, you must give the recipients all the rights that you have. You must make sure that they, too, receive or can get the source code. And you must show them these terms so they know their rights.
We protect your rights with two steps: (1) copyright the software, and (2) offer you this license which gives you legal permission to copy, distribute and/or modify the software.
Also, for each author's protection and ours, we want to make certain that everyone understands that there is no warranty for this free software. If the software is modified by someone else and passed on, we want its recipients to know that what they have is not the original, so that any problems introduced by others will not reflect on the original authors' reputations.
Finally, any free program is threatened constantly by software patents. We wish to avoid the danger that redistributors of a free program will individually obtain patent licenses, in effect making the program proprietary. To prevent this, we have made it clear that any patent must be licensed for everyone's free use or not licensed at all.
The precise terms and conditions for copying, distribution and modification follow.
Activities other than copying, distribution and modification are not covered by this License; they are outside its scope. The act of running the Program is not restricted, and the output from the Program is covered only if its contents constitute a work based on the Program (independent of having been made by running the Program). Whether that is true depends on what the Program does.
You may charge a fee for the physical act of transferring a copy, and you may at your option offer warranty protection in exchange for a fee.
These requirements apply to the modified work as a whole. If identifiable sections of that work are not derived from the Program, and can be reasonably considered independent and separate works in themselves, then this License, and its terms, do not apply to those sections when you distribute them as separate works. But when you distribute the same sections as part of a whole which is a work based on the Program, the distribution of the whole must be on the terms of this License, whose permissions for other licensees extend to the entire whole, and thus to each and every part regardless of who wrote it.
Thus, it is not the intent of this section to claim rights or contest your rights to work written entirely by you; rather, the intent is to exercise the right to control the distribution of derivative or collective works based on the Program.
In addition, mere aggregation of another work not based on the Program with the Program (or with a work based on the Program) on a volume of a storage or distribution medium does not bring the other work under the scope of this License.
The source code for a work means the preferred form of the work for making modifications to it. For an executable work, complete source code means all the source code for all modules it contains, plus any associated interface definition files, plus the scripts used to control compilation and installation of the executable. However, as a special exception, the source code distributed need not include anything that is normally distributed (in either source or binary form) with the major components (compiler, kernel, and so on) of the operating system on which the executable runs, unless that component itself accompanies the executable.
If distribution of executable or object code is made by offering access to copy from a designated place, then offering equivalent access to copy the source code from the same place counts as distribution of the source code, even though third parties are not compelled to copy the source along with the object code.
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This section is intended to make thoroughly clear what is believed to be a consequence of the rest of this License.
Each version is given a distinguishing version number. If the Program specifies a version number of this License which applies to it and "any later version", you have the option of following the terms and conditions either of that version or of any later version published by the Free Software Foundation. If the Program does not specify a version number of this License, you may choose any version ever published by the Free Software Foundation.
If you develop a new program, and you want it to be of the greatest possible use to the public, the best way to achieve this is to make it free software which everyone can redistribute and change under these terms.
To do so, attach the following notices to the program. It is safest to attach them to the start of each source file to most effectively convey the exclusion of warranty; and each file should have at least the "copyright" line and a pointer to where the full notice is found.
one line to give the program's name and an idea of what it does.
Copyright (C) 19yy name of author
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
Also add information on how to contact you by electronic and paper mail.
If the program is interactive, make it output a short notice like this when it starts in an interactive mode:
Gnomovision version 69, Copyright (C) 19yy name of author
Gnomovision comes with ABSOLUTELY NO WARRANTY; for details
type `show w'. This is free software, and you are welcome
to redistribute it under certain conditions; type `show c'
for details.
The hypothetical commands show w and show c should show
the appropriate parts of the General Public License. Of course, the
commands you use may be called something other than show w and
show c; they could even be mouse-clicks or menu items--whatever
suits your program.
You should also get your employer (if you work as a programmer) or your school, if any, to sign a "copyright disclaimer" for the program, if necessary. Here is a sample; alter the names:
Yoyodyne, Inc., hereby disclaims all copyright
interest in the program `Gnomovision'
(which makes passes at compilers) written
by James Hacker.
signature of Ty Coon, 1 April 1989
Ty Coon, President of Vice
This General Public License does not permit incorporating your program into proprietary programs. If your program is a subroutine library, you may consider it more useful to permit linking proprietary applications with the library. If this is what you want to do, use the GNU Library General Public License instead of this License.
Copyright (C) 2000 Free Software Foundation, Inc.
59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
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This is a general index of all issues discussed in this manual, with the
exception of the grep commands and command-line options.
grep usage: Usage
grep, Q&A: Usage
This is an alphabetical list of all grep commands, command-line
options, and environment variables.
*: Regular Expressions
+: Regular Expressions
--after-context: Invoking
--basic-regexp: Grep Programs
--before-context: Invoking
--binary: Invoking
--binary-files: Invoking
--byte-offset: Invoking
--colour: Invoking
--context: Invoking
--count: Invoking
--devices: Invoking
--directories: Invoking
--exclude: Invoking
--extended-regexp: Grep Programs
--file: Invoking
--files-with-matches: Invoking
--files-without-match: Invoking
--fixed-strings: Grep Programs
--help: Invoking
--ignore-case: Invoking
--include: Invoking
--invert-match: Invoking
--label: Invoking
--line-buffered: Invoking
--line-number: Invoking
--line-regexp: Invoking
--max-count: Invoking
--mmap: Invoking
--no-filename: Invoking
--no-messages: Invoking
--null: Invoking
--null-data: Invoking
--only-matching: Invoking
--perl-regexp: Grep Programs
--quiet: Invoking
--recursive: Invoking
--regexp=pattern--silent: Invoking
--text: Invoking
--unix-byte-offsets: Invoking
--version: Invoking
--With-filename: Invoking
--word-regexp: Invoking
-a: Invoking
-A: Invoking
-b: Invoking
-B: Invoking
-C: Invoking
-c: Invoking
-d: Invoking
-D: Invoking
-E: Grep Programs
-e: Invoking
-F: Grep Programs
-f: Invoking
-G: Grep Programs
-h: Invoking
-H: Invoking
-i: Invoking
-L: Invoking
-l: Invoking
-m: Invoking
-n: Invoking
-NUM: Invoking
-o: Invoking
-P: Grep Programs
-q: Invoking
-r: Invoking
-s: Invoking
-u: Invoking
-U: Invoking
-V: Invoking
-v: Invoking
-w: Invoking
-x: Invoking
-y: Invoking
-z: Invoking
-Z: Invoking
.: Regular Expressions
?: Regular Expressions
_N_GNU_nonoption_argv_flags_: Invoking
alnum: Regular Expressions
alpha: Regular Expressions
blank: Regular Expressions
cntrl: Regular Expressions
digit: Regular Expressions
graph: Regular Expressions
GREP_COLOR: Invoking
GREP_OPTIONS: Invoking
LANG: Invoking
LC_ALL: Invoking
LC_COLLATE: Invoking
LC_CTYPE: Invoking
LC_MESSAGES: Invoking
lower: Regular Expressions
POSIXLY_CORRECT: Invoking
print: Regular Expressions
punct: Regular Expressions
space: Regular Expressions
upper: Regular Expressions
xdigit: Regular Expressions
{n,m}: Regular Expressions
{n,}: Regular Expressions
{n}: Regular Expressions