Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
grep(1)			    General Commands Manual		       grep(1)

NAME
       grep, egrep, fgrep - search a file for a	pattern

SYNOPSIS
   Plain call with pattern
       pattern [file ...]

   Call	with (multiple)	-e pattern
       pattern]	...  [file ...]

   Call	with -f	file
       pattern_file] [file ...]

   Obsolescent:
       [expression] [file ...]

       [strings] [file ...]

DESCRIPTION
       The  command searches the input text files (standard input default) for
       lines matching a	pattern.  Normally, each line found is copied  to  the
       standard	 output.   supports  the  Basic	Regular	Expression syntax (see
       regexp(5)).  The	option supports	Extended Regular Expression (ERE) syn-
       tax  (see  regexp(5)).  The option searches for fixed strings using the
       fast Boyer-Moore	string searching algorithm.   The  and	options	 treat
       newlines	embedded in the	pattern	as alternation characters.  A null ex-
       pression	or string matches every	line.

       The forms and are maintained for	backward compatibility.	  The  use  of
       the and options is recommended for portability.

   Options
	      Extended regular expressions.
				  Each	pattern	specified is a sequence	of one
				  or more EREs.	 The EREs can be separated  by
				  newline  characters or given in separate ex-
				  pression options.  A pattern matches an  in-
				  put  line if any ERE in the sequence matches
				  the contents of the input line  without  its
				  trailing  newline character.	The same func-
				  tionality is obtained	by using

	      Fixed strings.	  Each pattern specified is a sequence of  one
				  or  more  strings.  Strings can be separated
				  by newline characters	or given  in  separate
				  expression  options.	 A  pattern matches an
				  input	line if	the line contains any  of  the
				  strings in the sequence.  The	same function-
				  ality	is obtained by using

	      Each line	is preceded by the block number	on which it was	found.
				  This is useful in locating disk  block  num-
				  bers	by  context.  Block numbers are	calcu-
				  lated	by dividing by 512 the number of bytes
				  that have been read from the file and	round-
				  ing down the result.

	      Only a count of matching lines is	printed.

	      Same as a	simple	  expression argument, but useful when the ex-
				  pression  begins  with a hyphen Multiple op-
				  tions	can be used to specify	multiple  pat-
				  terns;  an  input  line  is  selected	 if it
				  matches any of the specified patterns.

	      The regular	  expression and or strings list is taken from
				  the pattern_file.

	      Suppress printing	of filenames when searching multiple files.

	      Ignore uppercase/lowercase distinctions during comparisons.

	      Only the names of	files with matching lines are listed (once),
				  separated by newlines.  If standard input is
				  searched, a path name	of will	be written, in
				  the  POSIX  locale. In other locales,	may be
				  replaced by something	 more  appropriate  in
				  those	locales.

	      Each  line  is  preceded by its relative line number in the file
	      starting at 1.
				  The line  number  is	reset  for  each  file
				  searched.   This  option is ignored if or is
				  specified.

	      (Quiet)		  Do not write anything	to the	standard  out-
				  put,	regardless  of	matching  lines.  Exit
				  with zero  status  upon  finding  the	 first
				  matching  line.   Overrides any options that
				  would	produce	output.

	      Error messages produced for nonexistent or unreadable files  are
	      suppressed.

	      All lines	but those matching are printed.

	      Select only those	lines containing matches that
				  form	whole  words.  The  test  is  that the
				  matching substring must either be at the be-
				  ginning  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  charac-
				  ter.	Word-constituent  characters  are let-
				  ters,	digits,	and the	underscore.

	      (eXact)		  Matches are recognized only when the	entire
				  input	line matches the fixed string or regu-
				  lar expression.

       The file	name is	output in all the cases	in which output	 is  generated
       if  there  are more than	one input file,	unless the -h option is	speci-
       fied.  Care should be taken when	using the characters  and  in  expres-
       sion,  because  they are	also meaningful	to the shell.  It is safest to
       enclose the entire expression argument in single	quotes

EXTERNAL INFLUENCES
   Environment Variables
       determines the locale to	use for	the locale categories  when  both  and
       the corresponding environment variable (beginning with do not specify a
       locale.	If is not specified or is set to the empty string,  a  default
       of (see lang(5))	is used.

       determines  the	locale	to use to override any values for locale cate-
       gories specified	by the settings	of or any environment variables	begin-
       ning with

       determines  the	collating  sequence used in evaluating regular expres-
       sions.

       determines the interpretation of	text as	single byte and/or  multi-byte
       characters,  the	 classification	of characters as letters, the case in-
       formation for the option, and the characters matched by character class
       expressions in regular expressions.

       determines the language in which	messages are displayed.

       If  any	internationalization variable contains an invalid setting, the
       commands	behave as if all internationalization variables	are set	to See
       environ(5).

   International Code Set Support
       Single-byte and multi-byte character code sets are supported.

RETURN VALUE
       Upon completion,	returns	one of the following values:

	      One or more matches found.
	      No match found.
	      Syntax error or inaccessible file	(even if matches were found).

EXAMPLES
       In  the	POSIX  shell (sh(1)) the following example searches two	files,
       finding all lines containing occurrences	of any of four strings:

       Note that the single quotes are necessary to tell when the strings have
       ended and the file names	have begun.

       For the C shell (see csh(1)) the	following command can be used:

       To search a file	named containing the following entries:

       the command:

       prints:

       To  search  a file for lines that contain either	a or use either	of the
       following commands:

       Search all files	in the current directory for the string

       Search all files	in the current directory subtree for  the  string  and
       ensure that no error occurs due to file name expansion exceeding	system
       argument	list limits:

       The previous example does not print the name of files where string  ap-
       pears.  To force	to print file names, add a second argument to the com-
       mand portion of the command line:

       In this form, the first file name is that produced by  and  the	second
       file name is the	null file.

WARNINGS
       (XPG4  only.)  If the option is specified, the exit status will be zero
       if an input line	is selected, even if an	error  was  detected.	Other-
       wise, default actions will be performed.

       If  the	option is specified with non-word constituent characters, then
       the output is unexpected.

SEE ALSO
       sed(1), sh(1), regcomp(3C), environ(5), lang(5),	regexp(5).

STANDARDS CONFORMANCE
								       grep(1)

NAME | SYNOPSIS | DESCRIPTION | EXTERNAL INFLUENCES | RETURN VALUE | EXAMPLES | WARNINGS | SEE ALSO | STANDARDS CONFORMANCE

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=grep&sektion=1&manpath=HP-UX+11.22>

home | help