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NAME

       grep, egrep, fgrep, rgrep - 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,  three  variant  programs  egrep,  fgrep  and  rgrep  are
       available.   egrep  is  the  same  as  grep -E.   fgrep  is the same as
       grep -F.  rgrep is the same as grep -r.  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  (rather  than
              regular  expressions), 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  (PCRE, see
              below).  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.
              This option has the same effect as anchoring the expression with
              ^ and $.  (-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  (--)   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, 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.

       -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”  (BRE),  “extended” (ERE) and “perl” (PRCE). 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 only work
       if pcre is available in the 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  ()  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 ([...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

       The exit status is 0 if selected lines are found, and 1 if  not  found.
       If an error occurred the exit status is 2.  (Note: POSIX error handling
       code should check for '2' or greater.)

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), 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.



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