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GREP(1)				 User Commands			       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 is useful to protect patterns
	      beginning with hyphen-minus (-).	(-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  for	 tools
	      like zgrep, e.g., gzip -cd foo.gz | grep --label=foo something

       -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	 (--)  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	(--)   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 (--) between contiguous groups of matches.  With
	      the -o or --only-matching option,	 this  has  no	effect	and  a
	      warning is given.

   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, which means that directories  are  read
	      just  as	if  they  were	ordinary  files.   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.

       --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, -r, --recursive
	      Read all	files  under  each  directory,	recursively;  this  is
	      equivalent to the -d recurse option.

   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  two different versions of regular expression syntax:
       “basic” and  “extended.”	  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 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  [0-9A-Za-z],  except  the  latter  form
       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
       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.
       {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.2 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.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_
	      (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, 1999, 2000, 2002, 2005 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),   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.  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
       GNU's not Unix, but Unix is a beast; its plural form is Unixen.

GNU grep 2.5.1-cvs		  2006-08-18			       GREP(1)
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