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GREP(1) 										  GREP(1)

NAME
       grep, egrep, fgrep - print lines matching a pattern

SYNOPSIS
       grep [OPTIONS] PATTERN [FILE...]
       grep [OPTIONS] [-e PATTERN | -f FILE] [FILE...]

DESCRIPTION
       grep  searches  the  named  input  FILEs (or standard input if no files are named, or if a
       single hyphen-minus (-) is given as file name) for lines containing a match to  the  given
       PATTERN.  By default, grep prints the matching lines.

       In  addition,  two  variant  programs egrep and fgrep are available.  egrep is the same as
       grep -E.  fgrep is the same as grep -F.	Direct invocation as either  egrep  or	fgrep  is
       deprecated,  but  is  provided  to  allow historical applications that rely on them to run
       unmodified.

OPTIONS
   Generic Program Information
       --help Print a usage message briefly summarizing these command-line options and	the  bug-
	      reporting address, then exit.

       -V, --version
	      Print  the  version  number  of  grep  to the standard output stream.  This version
	      number should be included in all bug reports (see below).

   Matcher Selection
       -E, --extended-regexp
	      Interpret PATTERN as an extended regular	expression  (ERE,  see	below).   (-E  is
	      specified by POSIX.)

       -F, --fixed-strings
	      Interpret  PATTERN  as a list of fixed strings, separated by newlines, any of which
	      is to be matched.  (-F is specified by POSIX.)

       -G, --basic-regexp
	      Interpret PATTERN as a basic regular expression (BRE,  see  below).   This  is  the
	      default.

       -P, --perl-regexp
	      Interpret  PATTERN  as  a Perl regular expression.  This is highly experimental and
	      grep -P may warn of unimplemented features.

   Matching Control
       -e PATTERN, --regexp=PATTERN
	      Use PATTERN as the pattern.  This can be used to specify multiple search	patterns,
	      or to protect a pattern beginning with a hyphen (-).  (-e is specified by POSIX.)

       -f FILE, --file=FILE
	      Obtain  patterns	from  FILE, one per line.  The empty file contains zero patterns,
	      and therefore matches nothing.  (-f is specified by POSIX.)

       -i, --ignore-case
	      Ignore case distinctions in both the PATTERN and the input files.  (-i is specified
	      by POSIX.)

       -v, --invert-match
	      Invert  the  sense  of matching, to select non-matching lines.  (-v is specified by
	      POSIX.)

       -w, --word-regexp
	      Select only those lines containing matches that form whole words.  The test is that
	      the  matching substring must either be at the beginning of the line, or preceded by
	      a non-word constituent character.  Similarly, it must be either at the end  of  the
	      line  or followed by a non-word constituent character.  Word-constituent characters
	      are letters, digits, and the underscore.

       -x, --line-regexp
	      Select only those matches that exactly match the whole line.  (-x is  specified  by
	      POSIX.)

       -y     Obsolete synonym for -i.

   General Output Control
       -c, --count
	      Suppress	normal	output;  instead  print  a count of matching lines for each input
	      file.  With the -v, --invert-match option (see below),  count  non-matching  lines.
	      (-c is specified by POSIX.)

       --color[=WHEN], --colour[=WHEN]
	      Surround	the  matched  (non-empty)  strings,  matching  lines, context lines, file
	      names, line numbers, byte offsets, and separators (for fields and groups of context
	      lines)  with escape sequences to display them in color on the terminal.  The colors
	      are defined by the environment variable GREP_COLORS.   The  deprecated  environment
	      variable	GREP_COLOR  is	still  supported, but its setting does not have priority.
	      WHEN is never, always, or auto.

       -L, --files-without-match
	      Suppress normal output; instead print the name of each input  file  from	which  no
	      output  would  normally  have  been  printed.   The scanning will stop on the first
	      match.

       -l, --files-with-matches
	      Suppress normal output; instead print the name of each input file from which output
	      would  normally have been printed.  The scanning will stop on the first match.  (-l
	      is specified by POSIX.)

       -m NUM, --max-count=NUM
	      Stop reading a file after NUM matching lines.  If the input is standard input  from
	      a  regular  file, and NUM matching lines are output, grep 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.	When grep stops after NUM matching lines, it outputs any trailing
	      context  lines.  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.

       -o, --only-matching
	      Print only the matched (non-empty) parts of a matching line, with each such part on
	      a separate output line.

       -q, --quiet, --silent
	      Quiet; do not write anything to standard output.	Exit immediately with zero status
	      if  any  match  is  found,  even	if  an	error  was  detected.  Also see the -s or
	      --no-messages option.  (-q is specified by POSIX.)

       -s, --no-messages
	      Suppress error messages about nonexistent or unreadable files.   Portability  note:
	      unlike  GNU grep, 7th Edition Unix grep did not conform to POSIX, because it lacked
	      -q and its -s option behaved like GNU grep's -q option.  USG-style grep also lacked
	      -q  but  its  -s option behaved like GNU grep.  Portable shell scripts should avoid
	      both -q and -s and should redirect standard and error output to /dev/null  instead.
	      (-s is specified by POSIX.)

   Output Line Prefix Control
       -b, --byte-offset
	      Print the 0-based byte offset within the input file before each line of output.  If
	      -o (--only-matching) is specified, print the offset of the matching part itself.

       -H, --with-filename
	      Print the file name for each match.  This is the default when there  is  more  than
	      one file to search.

       -h, --no-filename
	      Suppress	the prefixing of file names on output.	This is the default when there is
	      only one file (or only standard input) to search.

       --label=LABEL
	      Display input actually coming from standard input as input coming from file  LABEL.
	      This is especially useful when implementing tools like zgrep, e.g., gzip -cd foo.gz
	      | grep --label=foo -H something.	See also the -H option.

       -n, --line-number
	      Prefix each line of output with the 1-based line number within its input file.  (-n
	      is specified by POSIX.)

       -T, --initial-tab
	      Make  sure  that	the first character of actual line content lies on a tab stop, so
	      that the alignment of tabs looks normal.	This is useful with options  that  prefix
	      their  output  to  the  actual  content:	-H,-n,	and  -b.  In order to improve the
	      probability that lines from a single file will all start at the same  column,  this
	      also causes the line number and byte offset (if present) to be printed in a minimum
	      size field width.

       -u, --unix-byte-offsets
	      Report Unix-style byte offsets.  This switch causes grep to report byte offsets  as
	      if  the  file  were  a Unix-style text file, i.e., with CR characters stripped off.
	      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.

       -Z, --null
	      Output a zero byte (the ASCII 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.

   Context Line Control
       -A NUM, --after-context=NUM
	      Print NUM lines of trailing context after matching lines.  Places a line containing
	      a group separator (described under --group-separator) between contiguous groups  of
	      matches.	 With  the -o or --only-matching option, this has no effect and a warning
	      is given.

       -B NUM, --before-context=NUM
	      Print NUM lines of leading context before matching lines.  Places a line containing
	      a  group separator (described under --group-separator) between contiguous groups of
	      matches.	With the -o or --only-matching option, this has no effect and  a  warning
	      is given.

       -C NUM, -NUM, --context=NUM
	      Print  NUM  lines  of  output  context.  Places a line containing a group separator
	      (described under --group-separator) between contiguous groups of matches.  With the
	      -o or --only-matching option, this has no effect and a warning is given.

       --group-separator=SEP
	      Use SEP as a group separator. By default SEP is double hyphen (--).

       --no-group-separator
	      Use empty string as a group separator.

   File and Directory Selection
       -a, --text
	      Process	a   binary   file  as  if  it  were  text;  this  is  equivalent  to  the
	      --binary-files=text option.

       --binary-files=TYPE
	      If the first few bytes of a file indicate  that  the  file  contains  binary  data,
	      assume  that  the  file  is  of  type  TYPE.   By default, TYPE is binary, 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: grep --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.

       -D ACTION, --devices=ACTION
	      If an input file is a device, FIFO  or  socket,  use  ACTION  to	process  it.   By
	      default,	ACTION	is  read,  which means that devices are read just as if they were
	      ordinary files.  If ACTION is skip, devices are silently skipped.

       -d ACTION, --directories=ACTION
	      If an input file is a directory, use ACTION to process it.  By default,  ACTION  is
	      read,  i.e.,  read  directories  just as if they were ordinary files.  If ACTION is
	      skip, silently skip directories.	If ACTION is recurse, read all files  under  each
	      directory,  recursively,	following  symbolic links only if they are on the command
	      line.  This is equivalent to the -r option.

       --exclude=GLOB
	      Skip files whose base name matches GLOB (using  wildcard	matching).   A	file-name
	      glob  can use *, ?, and [...]  as wildcards, and \ to quote a wildcard or backslash
	      character literally.

       --exclude-from=FILE
	      Skip files whose base name matches any of the file-name globs read from FILE (using
	      wildcard matching as described under --exclude).

       --exclude-dir=DIR
	      Exclude directories matching the pattern DIR from recursive searches.

       -I     Process a binary file as if it did not contain matching data; this is equivalent to
	      the --binary-files=without-match option.

       --include=GLOB
	      Search only files  whose	base  name  matches  GLOB  (using  wildcard  matching  as
	      described under --exclude).

       -r, --recursive
	      Read  all files under each directory, recursively, following symbolic links only if
	      they are on the command line.  This is equivalent to the -d recurse option.

       -R, --dereference-recursive
	      Read all files under each  directory,  recursively.   Follow  all  symbolic  links,
	      unlike -r.

   Other Options
       --line-buffered
	      Use line buffering on output.  This can cause a performance penalty.

       --mmap If  possible,  use  the  mmap(2)	system call to read input, instead of the default
	      read(2) 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.

       -U, --binary
	      Treat the file(s) as binary.  By default, under MS-DOS and MS-Windows, 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.

       -z, --null-data
	      Treat  the  input  as a set of lines, each terminated by a zero byte (the ASCII 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.

REGULAR EXPRESSIONS
       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  three  different  versions  of  regular  expression	syntax:  "basic,"
       "extended" and "perl." In GNU grep, there is  no  difference  in  available  functionality
       between	basic and extended syntaxes.  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.   Perl regular
       expressions give  additional  functionality,  and  are  documented  in  pcresyntax(3)  and
       pcrepattern(3), but may not be available on every system.

       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 meta-character with special meaning may be quoted by preceding it with a
       backslash.

       The period . matches any single character.

   Character Classes and Bracket Expressions
       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 names are self explanatory, and they are [:alnum:], [:alpha:], [:cntrl:],
       [:digit:],  [:graph:],  [:lower:],  [:print:],  [:punct:],   [:space:],	 [:upper:],   and
       [:xdigit:].   For example, [[:alnum:]] means the character class of numbers and letters in
       the current locale. In the C locale and ASCII character set encoding, this is the same  as
       [0-9A-Za-z].  (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 expression.)  Most
       meta-characters	lose  their  special  meaning  inside  bracket expressions.  To include a
       literal ] place it first in the list.  Similarly, to include a literal ^ place it anywhere
       but first.  Finally, to include a literal - place it last.

   Anchoring
       The  caret  ^  and the dollar sign $ are meta-characters that respectively match the empty
       string at the beginning and end of a line.

   The Backslash Character and Special Expressions
       The symbols \< and \> respectively match the empty string at the beginning and  end  of	a
       word.   The  symbol  \b matches the empty string at the edge of a word, and \B matches the
       empty string provided it's not at the edge of a word.  The symbol  \w  is  a  synonym  for
       [_[:alnum:]] and \W is a synonym for [^_[:alnum:]].

   Repetition
       A regular expression may be followed by one of several repetition operators:
       ?      The preceding item is optional and matched at most once.
       *      The preceding item will be matched zero or more times.
       +      The preceding item will be matched one or more times.
       {n}    The preceding item is matched exactly n times.
       {n,}   The preceding item is matched n or more times.
       {,m}   The preceding item is matched at most m times.  This is a GNU extension.
       {n,m}  The preceding item is matched at least n times, but not more than m times.

   Concatenation
       Two  regular expressions may be concatenated; the resulting regular expression matches any
       string formed by concatenating two substrings that  respectively  match	the  concatenated
       expressions.

   Alternation
       Two  regular  expressions  may  be  joined  by the infix operator |; the resulting regular
       expression matches any string matching either alternate expression.

   Precedence
       Repetition takes precedence over  concatenation,  which	in  turn  takes  precedence  over
       alternation.   A  whole	expression  may  be  enclosed  in  parentheses	to override these
       precedence rules and form a subexpression.

   Back References and Subexpressions
       The back-reference \n, where n is a single digit, matches the substring previously matched
       by the nth parenthesized subexpression of the regular expression.

   Basic vs Extended Regular Expressions
       In  basic  regular expressions the meta-characters ?, +, {, |, (, and ) lose their special
       meaning; instead use the backslashed versions \?, \+, \{, \|, \(, and \).

       Traditional egrep did not support the { meta-character,	and  some  egrep  implementations
       support	\{ instead, so portable scripts should avoid { in grep -E patterns and should use
       [{] to match a literal {.

       GNU grep -E 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 command
       grep -E '{1' searches for the two-character string {1 instead of reporting a syntax  error
       in  the	regular  expression.   POSIX  allows  this behavior as an extension, but portable
       scripts should avoid it.

ENVIRONMENT VARIABLES
       The behavior of grep is affected by the following environment variables.

       The locale for category LC_foo is specified by examining the three  environment	variables
       LC_ALL,	LC_foo,  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  the
       Brazilian Portuguese locale is used for the LC_MESSAGES category.  The C locale is used if
       none of these environment variables are set, if the locale catalog is not installed, or if
       grep was not compiled with national language support (NLS).

       GREP_OPTIONS
	      This  variable  specifies  default  options  to  be placed in front of any explicit
	      options.	  For	example,   if	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
	      This  variable  specifies the color used to highlight matched (non-empty) text.  It
	      is deprecated in favor of GREP_COLORS, but still supported.  The	mt,  ms,  and  mc
	      capabilities  of	GREP_COLORS have priority over it.  It can only specify the color
	      used to highlight the matching non-empty text in any matching line (a selected line
	      when  the  -v  command-line  option  is  omitted,  or  a	context  line  when -v is
	      specified).  The default is 01;31, which means a bold red foreground  text  on  the
	      terminal's default background.

       GREP_COLORS
	      Specifies  the  colors  and other attributes used to highlight various parts of the
	      output.  Its value is a colon-separated  list  of  capabilities  that  defaults  to
	      ms=01;31:mc=01;31:sl=:cx=:fn=35:ln=32:bn=32:se=36   with	the  rv  and  ne  boolean
	      capabilities omitted (i.e., false).  Supported capabilities are as follows.

	      sl=    SGR substring for whole selected lines (i.e., matching  lines  when  the  -v
		     command-line option is omitted, or non-matching lines when -v is specified).
		     If however the boolean rv capability and the -v command-line option are both
		     specified,  it  applies  to  context matching lines instead.  The default is
		     empty (i.e., the terminal's default color pair).

	      cx=    SGR substring for whole context lines (i.e., non-matching lines when the  -v
		     command-line option is omitted, or matching lines when -v is specified).  If
		     however the boolean rv capability and the -v command-line	option	are  both
		     specified,  it  applies to selected non-matching lines instead.  The default
		     is empty (i.e., the terminal's default color pair).

	      rv     Boolean value that  reverses  (swaps)  the  meanings  of  the  sl=  and  cx=
		     capabilities  when  the -v command-line option is specified.  The default is
		     false (i.e., the capability is omitted).

	      mt=01;31
		     SGR substring for matching non-empty text in  any	matching  line	(i.e.,	a
		     selected  line when the -v command-line option is omitted, or a context line
		     when -v is specified).  Setting this is equivalent to setting both  ms=  and
		     mc=  at  once  to the same value.	The default is a bold red text foreground
		     over the current line background.

	      ms=01;31
		     SGR substring for matching non-empty text in a selected line.  (This is only
		     used when the -v command-line option is omitted.)	The effect of the sl= (or
		     cx= if rv) capability remains active when this kicks in.  The default  is	a
		     bold red text foreground over the current line background.

	      mc=01;31
		     SGR  substring for matching non-empty text in a context line.  (This is only
		     used when the -v command-line option is specified.)  The effect of  the  cx=
		     (or sl= if rv) capability remains active when this kicks in.  The default is
		     a bold red text foreground over the current line background.

	      fn=35  SGR substring for file names prefixing any content line.  The default  is	a
		     magenta text foreground over the terminal's default background.

	      ln=32  SGR substring for line numbers prefixing any content line.  The default is a
		     green text foreground over the terminal's default background.

	      bn=32  SGR substring for byte offsets prefixing any content line.  The default is a
		     green text foreground over the terminal's default background.

	      se=36  SGR  substring for separators that are inserted between selected line fields
		     (:), between context line fields, (-), and between groups of adjacent  lines
		     when  nonzero  context  is  specified  (--).   The  default  is  a cyan text
		     foreground over the terminal's default background.

	      ne     Boolean value that prevents clearing to the end of line using Erase in  Line
		     (EL)  to  Right  (\33[K) each time a colorized item ends.	This is needed on
		     terminals on which EL is not supported.  It is otherwise useful on terminals
		     for  which  the  back_color_erase (bce) boolean terminfo capability does not
		     apply, when the chosen highlight colors do not  affect  the  background,  or
		     when EL is too slow or causes too much flicker.  The default is false (i.e.,
		     the capability is omitted).

	      Note that boolean capabilities have no =...  part.  They are omitted (i.e.,  false)
	      by default and become true when specified.

	      See  the	Select	Graphic  Rendition (SGR) section in the documentation of the text
	      terminal that  is  used  for  permitted  values  and  their  meaning  as	character
	      attributes.   These substring values are integers in decimal representation and can
	      be concatenated with semicolons.	grep takes care of assembling the result  into	a
	      complete SGR sequence (\33[...m).  Common values to concatenate include 1 for bold,
	      4 for underline, 5 for blink, 7 for inverse, 39 for default foreground color, 30 to
	      37  for  foreground colors, 90 to 97 for 16-color mode foreground colors, 38;5;0 to
	      38;5;255 for 88-color  and  256-color  modes  foreground	colors,  49  for  default
	      background  color,  40  to  47  for background colors, 100 to 107 for 16-color mode
	      background colors,  and  48;5;0  to  48;5;255  for  88-color  and  256-color  modes
	      background colors.

       LC_ALL, LC_COLLATE, LANG
	      These  variables	specify  the locale for the LC_COLLATE category, which determines
	      the collating sequence used to interpret range expressions like [a-z].

       LC_ALL, LC_CTYPE, LANG
	      These variables specify the locale for the LC_CTYPE category, which determines  the
	      type of characters, e.g., which characters are whitespace.

       LC_ALL, LC_MESSAGES, LANG
	      These  variables	specify the locale for the LC_MESSAGES category, which determines
	      the language that grep uses for messages.   The  default	C  locale  uses  American
	      English messages.

       POSIXLY_CORRECT
	      If set, grep behaves as POSIX requires; otherwise, grep behaves more like other GNU
	      programs.  POSIX 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	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_
	      (Here  N	is  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.

EXIT STATUS
       Normally, the 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.  Note, however, that POSIX only mandates, for programs  such  as
       grep,  cmp,  and  diff,	that  the  exit  status in case of error be greater than 1; it is
       therefore advisable, for the sake of portability, to use logic that tests for this general
       condition instead of strict equality with 2.

COPYRIGHT
       Copyright 1998-2000, 2002, 2005-2014 Free Software Foundation, Inc.

       This  is  free software; see the source for copying conditions.	There is NO warranty; not
       even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

BUGS
   Reporting Bugs
       Email  bug  reports  to	<bug-grep@gnu.org>,  a	 mailing   list   whose   web	page   is
       <http://lists.gnu.org/mailman/listinfo/bug-grep>.   grep's Savannah bug tracker is located
       at <http://savannah.gnu.org/bugs/?group=grep>.

   Known Bugs
       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.

SEE ALSO
   Regular Manual Pages
       awk(1), cmp(1), diff(1), find(1), gzip(1), perl(1), sed(1), sort(1),  xargs(1),	zgrep(1),
       mmap(2), read(2), pcre(3), pcresyntax(3), pcrepattern(3), terminfo(5), glob(7), regex(7).

   POSIX Programmer's Manual Page
       grep(1p).

   TeXinfo Documentation
       The  full  documentation for grep is maintained as a TeXinfo manual, which you can read at
       http://www.gnu.org/software/grep/manual/.  If the info  and  grep  programs  are  properly
       installed at your site, the command

	      info grep

       should give you access to the complete manual.

NOTES
       This  man  page	is  maintained only fitfully; the full documentation is often more up-to-
       date.

       GNU's not Unix, but Unix is a beast; its plural form is Unixen.

User Commands				  GNU grep 2.16 				  GREP(1)
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