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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 the file
       name - is given) 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.

OPTIONS
       -A NUM, --after-context=NUM
	      Print NUM lines of trailing context after matching lines.  Places a line containing
	      -- between contiguous groups of matches.

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

       -B NUM, --before-context=NUM
	      Print NUM lines of leading context before matching lines.  Places a line containing
	      -- between contiguous groups of matches.

       -C NUM, --context=NUM
	      Print  NUM lines of output context.  Places a line containing -- between contiguous
	      groups of matches.

       -b, --byte-offset
	      Print the byte offset within the input file before each line of output.

       --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 nor-
	      mally 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.

       --colour[=WHEN], --color[=WHEN]
	      Surround the matching string with the marker find in GREP_COLOR  environment  vari-
	      able. WHEN may be `never', `always', or `auto'

       -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.

       -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.

       -E, --extended-regexp
	      Interpret PATTERN as an extended regular expression (see below).

       -e PATTERN, --regexp=PATTERN
	      Use PATTERN as the pattern; useful to protect patterns beginning with -.

       -F, --fixed-strings
	      Interpret PATTERN as a list of fixed strings, separated by newlines, any	of  which
	      is  to  be  matched.  -P, --perl-regexp Interpret PATTERN as a Perl regular expres-
	      sion.

       -f FILE, --file=FILE
	      Obtain patterns from FILE, one per line.	The empty file	contains  zero	patterns,
	      and therefore matches nothing.

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

       -H, --with-filename
	      Print the filename for each match.

       -h, --no-filename
	      Suppress the prefixing of filenames on output when multiple files are searched.

       --help Output a brief help message.

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

       -i, --ignore-case
	      Ignore case distinctions in both the PATTERN and the input files.

       -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.

       -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.

       --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.  How-
	      ever, --mmap can cause undefined behavior (including core dumps) if an  input  file
	      shrinks while grep is operating, or if an I/O error occurs.

       -n, --line-number
	      Prefix each line of output with the line number within its input file.

       -o, --only-matching
	      Show only the part of a matching line that matches PATTERN.

       --label=LABEL
	      Displays 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

       --line-buffering
	      Use line buffering, it can be a performance penality.

       -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-mes-
	      sages option.

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

	 --include=PATTERN
	      Recurse in directories only searching file matching PATTERN.

	 --exclude=PATTERN
	      Recurse in directories skip file matching PATTERN.

       -s, --no-messages
	      Suppress error messages about nonexistent or unreadable files.   Portability  note:
	      unlike  GNU  grep, traditional grep did not conform to POSIX.2, because traditional
	      grep lacked a -q option and its -s option behaved like GNU grep's -q option.  Shell
	      scripts intended to be portable to traditional grep should avoid both -q and -s and
	      should redirect output to /dev/null instead.

       -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).  Specify-
	      ing -U overrules this guesswork, causing all files to be read  and  passed  to  the
	      matching mechanism verbatim; if the file is a text file with CR/LF pairs at the end
	      of each line, this will cause some regular expressions to fail.  This option has no
	      effect on platforms other than MS-DOS and MS-Windows.

       -u, --unix-byte-offsets
	      Report  Unix-style byte offsets.	This switch causes grep to report byte offsets as
	      if the file were 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.

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

       -v, --invert-match
	      Invert the sense of matching, to select non-matching lines.

       -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.

       -y     Obsolete synonym for -i.

       -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.

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  com-
       bine 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 fol-
       lowing description applies to extended regular expressions; differences for basic  regular
       expressions are summarized afterwards.

       The fundamental building blocks are the regular expressions that match a single character.
       Most characters, including all letters and digits,  are	regular  expressions  that  match
       themselves.   Any  metacharacter with special meaning may be quoted by preceding it with a
       backslash.

       A 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  expres-
       sions, 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
       list.)  Most metacharacters lose their special meaning inside lists.  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.

       The period .  matches any single character.  The symbol \w is a	synonym  for  [[:alnum:]]
       and \W is a synonym for [^[:alnum]].

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

       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.
       {n,m}  The preceding item is matched at least n times, but not more than m times.

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

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

       Repetition takes precedence over concatenation, which in turn takes precedence over alter-
       nation.	A whole subexpression may be enclosed in parentheses to override these precedence
       rules.

       The backreference \n, where n is a single digit, matches the substring previously  matched
       by the nth parenthesized subexpression of the regular expression.

       In  basic  regular  expressions the metacharacters ?, +, {, |, (, and ) lose their special
       meaning; instead use the backslashed versions \?, \+, \{, \|, \(, and \).

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

       GNU egrep attempts to support traditional usage by assuming that { is not  special  if  it
       would  be  the start of an invalid interval specification.  For example, the shell command
       egrep '{1' searches for the two-character string {1 instead of reporting a syntax error in
       the  regular  expression.   POSIX.2  allows  this  behavior  as an extension, but portable
       scripts should avoid it.

ENVIRONMENT VARIABLES
       Grep's behavior is affected by the following environment variables.

       A locale LC_foo is specified by examining the three environment variables LC_ALL,  LC_foo,
       LANG,  in that order.  The first of these variables that is set specifies the locale.  For
       example, if LC_ALL is not set, but LC_MESSAGES is set to pt_BR, then Brazilian  Portuguese
       is  used  for  the  LC_MESSAGES locale.	The C locale is used if none of these environment
       variables are set, or if the locale catalog is not installed, or if grep was not  compiled
       with national language support (NLS).

       GREP_OPTIONS
	      This  variable  specifies  default  options  to  be placed in front of any explicit
	      options.	For example, if GREP_OPTIONS is '--binary-files=without-match  --directo-
	      ries=skip',  grep  behaves  as  if the two options --binary-files=without-match and
	      --directories=skip had been specified before any explicit options.  Option specifi-
	      cations 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
	      Specifies the marker for highlighting.

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

       LC_ALL, LC_CTYPE, LANG
	      These  variables	specify the LC_CTYPE locale, which determines the type of charac-
	      ters, e.g., which characters are whitespace.

       LC_ALL, LC_MESSAGES, LANG
	      These variables specify the LC_MESSAGES locale, 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  wild-
	      card  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.

DIAGNOSTICS
       Normally, exit status is 0 if selected lines are found and 1 otherwise.	But the exit sta-
       tus  is	2 if an error occurred, unless the -q or --quiet or --silent option is used and a
       selected line is found.

BUGS
       Email bug reports to bug-gnu-utils@gnu.org.  Be sure to include the word "grep"	somewhere
       in the "Subject:" field.

       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.

       Backreferences are very slow, and may require exponential time.

ATTRIBUTES
       See attributes(5) for descriptions of the following attributes:

       +--------------------+-----------------+
       |  ATTRIBUTE TYPE    | ATTRIBUTE VALUE |
       +--------------------+-----------------+
       |Availability	    | SUNWggrp	      |
       +--------------------+-----------------+
       |Interface Stability | Volatile	      |
       +--------------------+-----------------+
NOTES
       Source for ggrep is available on http://opensolaris.org.

GNU Project				    2002/01/22					  GREP(1)
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