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GREP(1)			FreeBSD	General	Commands Manual		       GREP(1)

NAME
     grep, egrep, fgrep, rgrep -- file pattern searcher

SYNOPSIS
     grep [-abcdDEFGHhIiLlmnOopqRSsUVvwxz] [-A num] [-B	num] [-C[num]]
	  [-e pattern] [-f file] [--binary-files=value]	[--color[=when]]
	  [--colour[=when]] [--context[=num]] [--label]	[--line-buffered]
	  [--null] [pattern] [file ...]

DESCRIPTION
     The grep utility searches any given input files, selecting	lines that
     match one or more patterns.  By default, a	pattern	matches	an input line
     if	the regular expression (RE) in the pattern matches the input line
     without its trailing newline.  An empty expression	matches	every line.
     Each input	line that matches at least one of the patterns is written to
     the standard output.

     grep is used for simple patterns and basic	regular	expressions (BREs);
     egrep can handle extended regular expressions (EREs).  See	re_format(7)
     for more information on regular expressions.  fgrep is quicker than both
     grep and egrep, but can only handle fixed patterns	(i.e., it does not
     interpret regular expressions).  Patterns may consist of one or more
     lines, allowing any of the	pattern	lines to match a portion of the	input.

     The following options are available:

     -A	num, --after-context=num
	     Print num lines of	trailing context after each match.  See	also
	     the -B and	-C options.

     -a, --text
	     Treat all files as	ASCII text.  Normally grep will	simply print
	     ``Binary file ... matches'' if files contain binary characters.
	     Use of this option	forces grep to output lines matching the spec-
	     ified pattern.

     -B	num, --before-context=num
	     Print num lines of	leading	context	before each match.  See	also
	     the -A and	-C options.

     -b, --byte-offset
	     The offset	in bytes of a matched pattern is displayed in front of
	     the respective matched line.

     -C[num], --context[=num]
	     Print num lines of	leading	and trailing context surrounding each
	     match.  The default value of num is ``2'' and is equivalent to
	     ``-A 2 -B 2''.  Note: no whitespace may be	given between the
	     option and	its argument.

     -c, --count
	     Only a count of selected lines is written to standard output.

     --colour=[when], --color=[when]
	     Mark up the matching text with the	expression stored in the
	     GREP_COLOR	environment variable.  The possible values of when are
	     ``never'',	``always'' and ``auto''.

     -D	action,	--devices=action
	     Specify the demanded action for devices, FIFOs and	sockets.  The
	     default action is ``read'', which means, that they	are read as if
	     they were normal files.  If the action is set to ``skip'',
	     devices are silently skipped.

     -d	action,	--directories=action
	     Specify the demanded action for directories.  It is ``read'' by
	     default, which means that the directories are read	in the same
	     manner as normal files.  Other possible values are	``skip'' to
	     silently ignore the directories, and ``recurse'' to read them
	     recursively, which	has the	same effect as the -R and -r option.

     -E, --extended-regexp
	     Interpret pattern as an extended regular expression (i.e.,	force
	     grep to behave as egrep).

     -e	pattern, --regexp=pattern
	     Specify a pattern used during the search of the input: an input
	     line is selected if it matches any	of the specified patterns.
	     This option is most useful	when multiple -e options are used to
	     specify multiple patterns,	or when	a pattern begins with a	dash
	     (`-').

     --exclude pattern
	     If	specified, it excludes files matching the given	filename
	     pattern from the search.  Note that --exclude and --include pat-
	     terns are processed in the	order given.  If a name	patches	multi-
	     ple patterns, the latest matching rule wins.  If no --include
	     pattern is	specified, all files are searched that are not
	     excluded.	Patterns are matched to	the full path specified, not
	     only to the filename component.

     --exclude-dir pattern
	     If	-R is specified, it excludes directories matching the given
	     filename pattern from the search.	Note that --exclude-dir	and
	     --include-dir patterns are	processed in the order given.  If a
	     name patches multiple patterns, the latest	matching rule wins.
	     If	no --include-dir pattern is specified, all directories are
	     searched that are not excluded.

     -F, --fixed-strings
	     Interpret pattern as a set	of fixed strings (i.e.,	force grep to
	     behave as fgrep).

     -f	file, --file=file
	     Read one or more newline separated	patterns from file.  Empty
	     pattern lines match every input line.  Newlines are not consid-
	     ered part of a pattern.  If file is empty,	nothing	is matched.

     -G, --basic-regexp
	     Interpret pattern as a basic regular expression (i.e., force grep
	     to	behave as traditional grep).

     -H	     Always print filename headers with	output lines.

     -h, --no-filename
	     Never print filename headers (i.e., filenames) with output	lines.

     --help  Print a brief help	message.

     -I	     Ignore binary files.  This	option is equivalent to	the
	     ``--binary-file=without-match'' option.

     -i, --ignore-case
	     Perform case insensitive matching.	 By default, grep is case sen-
	     sitive.

     --include pattern
	     If	specified, only	files matching the given filename pattern are
	     searched.	Note that --include and	--exclude patterns are pro-
	     cessed in the order given.	 If a name patches multiple patterns,
	     the latest	matching rule wins.  Patterns are matched to the full
	     path specified, not only to the filename component.

     --include-dir pattern
	     If	-R is specified, only directories matching the given filename
	     pattern are searched.  Note that --include-dir and	--exclude-dir
	     patterns are processed in the order given.	 If a name patches
	     multiple patterns,	the latest matching rule wins.

     -L, --files-without-match
	     Only the names of files not containing selected lines are written
	     to	standard output.  Pathnames are	listed once per	file searched.
	     If	the standard input is searched,	the string ``(standard
	     input)'' is written unless	a --label is specified.

     -l, --files-with-matches
	     Only the names of files containing	selected lines are written to
	     standard output.  grep will only search a file until a match has
	     been found, making	searches potentially less expensive.  Path-
	     names are listed once per file searched.  If the standard input
	     is	searched, the string ``(standard input)'' is written unless a
	     --label is	specified.

     --label
	     Label to use in place of ``(standard input)'' for a file name
	     where a file name would normally be printed.  This	option applies
	     to	-H, -L,	and -l.

     --mmap  Use mmap(2) instead of read(2) to read input, which can result in
	     better performance	under some circumstances but can cause unde-
	     fined behaviour.

     -m	num, --max-count=num
	     Stop reading the file after num matches.

     -n, --line-number
	     Each output line is preceded by its relative line number in the
	     file, starting at line 1.	The line number	counter	is reset for
	     each file processed.  This	option is ignored if -c, -L, -l, or -q
	     is	specified.

     --null  Prints a zero-byte	after the file name.

     -O	     If	-R is specified, follow	symbolic links only if they were
	     explicitly	listed on the command line.  The default is not	to
	     follow symbolic links.

     -o, --only-matching
	     Prints only the matching part of the lines.

     -p	     If	-R is specified, no symbolic links are followed.  This is the
	     default.

     -q, --quiet, --silent
	     Quiet mode: suppress normal output.  grep will only search	a file
	     until a match has been found, making searches potentially less
	     expensive.

     -R, -r, --recursive
	     Recursively search	subdirectories listed.	(i.e., force grep to
	     behave as rgrep).

     -S	     If	-R is specified, all symbolic links are	followed.  The default
	     is	not to follow symbolic links.

     -s, --no-messages
	     Silent mode.  Nonexistent and unreadable files are	ignored	(i.e.,
	     their error messages are suppressed).

     -U, --binary
	     Search binary files, but do not attempt to	print them.

     -u	     This option has no	effect and is provided only for	compatibility
	     with GNU grep.

     -V, --version
	     Display version information and exit.

     -v, --invert-match
	     Selected lines are	those not matching any of the specified	pat-
	     terns.

     -w, --word-regexp
	     The expression is searched	for as a word (as if surrounded	by
	     `[[:<:]]' and `[[:>:]]'; see re_format(7)).

     -x, --line-regexp
	     Only input	lines selected against an entire fixed string or regu-
	     lar expression are	considered to be matching lines.

     -y	     Equivalent	to -i.	Obsoleted.

     -z, --null-data
	     Treat input and output data as sequences of lines terminated by a
	     zero-byte instead of a newline.

     --binary-files=value
	     Controls searching	and printing of	binary files.  Options are:
	     binary (default)  Search binary files but do not print them.
	     without-match     Do not search binary files.
	     text	       Treat all files as text.

     --line-buffered
	     Force output to be	line buffered.	By default, output is line
	     buffered when standard output is a	terminal and block buffered
	     otherwise.

     If	no file	arguments are specified, the standard input is used.  Addi-
     tionally, ``-'' may be used in place of a file name, anywhere that	a file
     name is accepted, to read from standard input.  This includes both	-f and
     file arguments.

EXIT STATUS
     The grep utility exits with one of	the following values:

     0	   One or more lines were selected.
     1	   No lines were selected.
     >1	   An error occurred.

EXAMPLES
     -	 To find all occurrences of the	word `patricia'	in a file:

	       $ grep 'patricia' myfile

     -	 To find all occurrences of the	pattern	`.Pp' at the beginning of a
	 line:

	       $ grep '^\.Pp' myfile

	 The apostrophes ensure	the entire expression is evaluated by grep
	 instead of by the user's shell.  The caret `^'	matches	the null
	 string	at the beginning of a line, and	the `\'	escapes	the `.', which
	 would otherwise match any character.

     -	 To find all lines in a	file which do not contain the words `foo' or
	 `bar':

	       $ grep -v -e 'foo' -e 'bar' myfile

     -	 A simple example of an	extended regular expression:

	       $ egrep '19|20|25' calendar

	 Peruses the file `calendar' looking for either	19, 20,	or 25.

SEE ALSO
     ed(1), ex(1), sed(1), zgrep(1), re_format(7)

STANDARDS
     The grep utility is compliant with	the IEEE Std 1003.1-2008 (``POSIX.1'')
     specification.

     The flags [-AaBbCDdGHhILmoPRSUVw] are extensions to that specification,
     and the behaviour of the -f flag when used	with an	empty pattern file is
     left undefined.

     All long options are provided for compatibility with GNU versions of this
     utility.

     Historic versions of the grep utility also	supported the flags [-ruy].
     This implementation supports those	options; however, their	use is
     strongly discouraged.

HISTORY
     The grep command first appeared in	Version	6 AT&T UNIX.

FreeBSD	Ports 11.2		August 21, 2018		    FreeBSD Ports 11.2

NAME | SYNOPSIS | DESCRIPTION | EXIT STATUS | EXAMPLES | SEE ALSO | STANDARDS | HISTORY

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