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PCREGREP(1)							   PCREGREP(1)

NAME
       pcregrep - a grep with Perl-compatible regular expressions.

SYNOPSIS
       pcregrep [options] [long options] [pattern] [path1 path2 ...]

DESCRIPTION

       pcregrep	 searches  files  for  character  patterns, in the same way as
       other grep commands do, but it uses the PCRE regular expression library
       to support patterns that are compatible with the regular expressions of
       Perl 5. See pcrepattern(3) for a full description of syntax and	seman‐
       tics of the regular expressions that PCRE supports.

       Patterns,  whether  supplied on the command line or in a separate file,
       are given without delimiters. For example:

	 pcregrep Thursday /etc/motd

       If you attempt to use delimiters (for example, by surrounding a pattern
       with  slashes,  as  is common in Perl scripts), they are interpreted as
       part of the pattern. Quotes can of course be used to  delimit  patterns
       on  the	command	 line  because	they are interpreted by the shell, and
       indeed quotes are required if a pattern contains white space  or	 shell
       metacharacters.

       The  first  argument that follows any option settings is treated as the
       single pattern to be matched when neither -e nor -f is  present.	  Con‐
       versely,	 when  one  or	both of these options are used to specify pat‐
       terns, all arguments are treated as path names. At least one of -e, -f,
       or an argument pattern must be provided.

       If no files are specified, pcregrep reads the standard input. The stan‐
       dard input can also be referenced by a  name  consisting	 of  a	single
       hyphen.	For example:

	 pcregrep some-pattern /file1 - /file3

       By  default, each line that matches a pattern is copied to the standard
       output, and if there is more than one file, the file name is output  at
       the start of each line, followed by a colon. However, there are options
       that can change how pcregrep behaves.  In  particular,  the  -M	option
       makes  it  possible  to	search for patterns that span line boundaries.
       What defines a line  boundary  is  controlled  by  the  -N  (--newline)
       option.

       The amount of memory used for buffering files that are being scanned is
       controlled by a parameter that can be set by the --buffer-size  option.
       The  default  value  for	 this  parameter is specified when pcregrep is
       built, with the default default being 20K.  A  block  of	 memory	 three
       times  this  size  is used (to allow for buffering "before" and "after"
       lines). An error occurs if a line overflows the buffer.

       Patterns can be no longer than 8K or BUFSIZ  bytes,  whichever  is  the
       greater.	  BUFSIZ  is defined in <stdio.h>. When there is more than one
       pattern (specified by the use of -e and/or -f), each pattern is applied
       to  each	 line  in the order in which they are defined, except that all
       the -e patterns are tried before the -f patterns.

       By default, as soon as one pattern matches a line, no further  patterns
       are considered. However, if --colour (or --color) is used to colour the
       matching substrings, or if --only-matching, --file-offsets, or  --line-
       offsets	is  used  to  output  only  the	 part of the line that matched
       (either shown literally, or as an offset), scanning resumes immediately
       following  the  match,  so that further matches on the same line can be
       found. If there are multiple  patterns,	they  are  all	tried  on  the
       remainder  of  the  line, but patterns that follow the one that matched
       are not tried on the earlier part of the line.

       This behaviour means that the order  in	which  multiple	 patterns  are
       specified  can affect the output when one of the above options is used.
       This is no longer the same behaviour as GNU grep, which now manages  to
       display	earlier	 matches  for  later  patterns (as long as there is no
       overlap).

       Patterns that can match an empty string are accepted, but empty	string
       matches	 are   never   recognized.   An	  example   is	 the   pattern
       "(super)?(man)?", in which all components are  optional.	 This  pattern
       finds  all  occurrences	of  both "super" and "man"; the output differs
       from matching with "super|man" when only the  matching  substrings  are
       being shown.

       If  the	LC_ALL	or LC_CTYPE environment variable is set, pcregrep uses
       the value to set a locale when calling the PCRE library.	 The  --locale
       option can be used to override this.

SUPPORT FOR COMPRESSED FILES

       It  is  possible	 to compile pcregrep so that it uses libz or libbz2 to
       read files whose names end in .gz or .bz2, respectively. You  can  find
       out whether your binary has support for one or both of these file types
       by running it with the --help option. If the appropriate support is not
       present,	 files are treated as plain text. The standard input is always
       so treated.

BINARY FILES

       By default, a file that contains a binary zero byte  within  the	 first
       1024  bytes is identified as a binary file, and is processed specially.
       (GNU grep also  identifies  binary  files  in  this  manner.)  See  the
       --binary-files  option for a means of changing the way binary files are
       handled.

OPTIONS

       The order in which some of the options appear can  affect  the  output.
       For  example,  both  the	 -h and -l options affect the printing of file
       names. Whichever comes later in the command line will be the  one  that
       takes  effect.  Similarly,  except  where  noted below, if an option is
       given twice, the later setting is used. Numerical  values  for  options
       may  be	followed  by  K	 or  M,	 to  signify multiplication by 1024 or
       1024*1024 respectively.

       --	 This terminates the list of options. It is useful if the next
		 item  on  the command line starts with a hyphen but is not an
		 option. This allows for the processing of patterns and	 file‐
		 names that start with hyphens.

       -A number, --after-context=number
		 Output	 number	 lines of context after each matching line. If
		 filenames and/or line numbers are being output, a hyphen sep‐
		 arator	 is  used  instead of a colon for the context lines. A
		 line containing "--" is output between each group  of	lines,
		 unless	 they  are  in	fact contiguous in the input file. The
		 value of number is expected to be relatively small.  However,
		 pcregrep guarantees to have up to 8K of following text avail‐
		 able for context output.

       -a, --text
		 Treat binary files as text. This is equivalent	 to  --binary-
		 files=text.

       -B number, --before-context=number
		 Output	 number lines of context before each matching line. If
		 filenames and/or line numbers are being output, a hyphen sep‐
		 arator	 is  used  instead of a colon for the context lines. A
		 line containing "--" is output between each group  of	lines,
		 unless	 they  are  in	fact contiguous in the input file. The
		 value of number is expected to be relatively small.  However,
		 pcregrep guarantees to have up to 8K of preceding text avail‐
		 able for context output.

       --binary-files=word
		 Specify how binary files are to be processed. If the word  is
		 "binary"  (the	 default),  pattern  matching  is performed on
		 binary files, but the only  output  is	 "Binary  file	<name>
		 matches"  when a match succeeds. If the word is "text", which
		 is equivalent to the -a or --text option,  binary  files  are
		 processed  in	the  same way as any other file. In this case,
		 when a match succeeds, the  output  may  be  binary  garbage,
		 which	can  have  nasty effects if sent to a terminal. If the
		 word is  "without-match",  which  is  equivalent  to  the  -I
		 option,  binary  files	 are  not  processed  at all; they are
		 assumed not to be of interest.

       --buffer-size=number
		 Set the parameter that controls how much memory is  used  for
		 buffering files that are being scanned.

       -C number, --context=number
		 Output	 number	 lines	of  context both before and after each
		 matching line.	 This is equivalent to setting both -A and  -B
		 to the same value.

       -c, --count
		 Do  not output individual lines from the files that are being
		 scanned; instead output the number of lines that would other‐
		 wise  have  been  shown. If no lines are selected, the number
		 zero is output. If several files are  are  being  scanned,  a
		 count	is  output  for each of them. However, if the --files-
		 with-matches option is also  used,  only  those  files	 whose
		 counts are greater than zero are listed. When -c is used, the
		 -A, -B, and -C options are ignored.

       --colour, --color
		 If this option is given without any data, it is equivalent to
		 "--colour=auto".   If	data  is required, it must be given in
		 the same shell item, separated by an equals sign.

       --colour=value, --color=value
		 This option specifies under what circumstances the parts of a
		 line that matched a pattern should be coloured in the output.
		 By default, the output is not coloured. The value  (which  is
		 optional,  see above) may be "never", "always", or "auto". In
		 the latter case, colouring happens only if the standard  out‐
		 put  is connected to a terminal. More resources are used when
		 colouring is enabled, because pcregrep has to search for  all
		 possible  matches in a line, not just one, in order to colour
		 them all.

		 The colour that is used can be specified by setting the envi‐
		 ronment variable PCREGREP_COLOUR or PCREGREP_COLOR. The value
		 of this variable should be a string of two numbers, separated
		 by  a	semicolon.  They  are copied directly into the control
		 string for setting colour  on	a  terminal,  so  it  is  your
		 responsibility	 to ensure that they make sense. If neither of
		 the environment variables is  set,  the  default  is  "1;31",
		 which gives red.

       -D action, --devices=action
		 If  an	 input	path  is  not  a  regular file or a directory,
		 "action" specifies how it is to be  processed.	 Valid	values
		 are "read" (the default) or "skip" (silently skip the path).

       -d action, --directories=action
		 If an input path is a directory, "action" specifies how it is
		 to be processed.  Valid values are  "read"  (the  default  in
		 non-Windows  environments,  for compatibility with GNU grep),
		 "recurse" (equivalent to the -r option), or "skip"  (silently
		 skip  the  path, the default in Windows environments). In the
		 "read" case, directories are read as if  they	were  ordinary
		 files.	 In  some  operating  systems  the effect of reading a
		 directory like this is an immediate end-of-file; in others it
		 may provoke an error.

       -e pattern, --regex=pattern, --regexp=pattern
		 Specify a pattern to be matched. This option can be used mul‐
		 tiple times in order to specify several patterns. It can also
		 be  used  as a way of specifying a single pattern that starts
		 with a hyphen. When -e is used, no argument pattern is	 taken
		 from  the  command  line;  all	 arguments are treated as file
		 names. There is no limit to the number of patterns. They  are
		 applied  to  each line in the order in which they are defined
		 until one matches.

		 If -f is used with -e, the command line patterns are  matched
		 first, followed by the patterns from the file(s), independent
		 of the order in which these options are specified. Note  that
		 multiple  use	of -e is not the same as a single pattern with
		 alternatives. For example, X|Y finds the first character in a
		 line  that  is	 X or Y, whereas if the two patterns are given
		 separately, with X first, pcregrep finds X if it is  present,
		 even if it follows Y in the line. It finds Y only if there is
		 no X in the line. This matters only if you are	 using	-o  or
		 --colo(u)r to show the part(s) of the line that matched.

       --exclude=pattern
		 Files (but not directories) whose names match the pattern are
		 skipped without being processed. This applies to  all	files,
		 whether  listed  on  the  command line, obtained from --file-
		 list, or by scanning a directory. The pattern is a PCRE regu‐
		 lar expression, and is matched against the final component of
		 the file name, not the	 entire	 path.	The  -F,  -w,  and  -x
		 options do not apply to this pattern. The option may be given
		 any number of times in order to specify multiple patterns. If
		 a  file  name matches both an --include and an --exclude pat‐
		 tern, it is excluded. There is no short form for this option.

       --exclude-from=filename
		 Treat each non-empty line of the file	as  the	 data  for  an
		 --exclude option. What constitutes a newline when reading the
		 file is the operating system's default. The --newline	option
		 has  no  effect on this option. This option may be given more
		 than once in order to specify a number of files to read.

       --exclude-dir=pattern
		 Directories whose names match the pattern are skipped without
		 being	processed,  whatever  the  setting  of the --recursive
		 option. This applies to all directories,  whether  listed  on
		 the command line, obtained from --file-list, or by scanning a
		 parent directory. The pattern is a PCRE  regular  expression,
		 and  is  matched against the final component of the directory
		 name, not the entire path. The -F, -w, and -x options do  not
		 apply	to this pattern. The option may be given any number of
		 times in order to specify more than one pattern. If a	direc‐
		 tory  matches	both  --include-dir  and  --exclude-dir, it is
		 excluded. There is no short form for this option.

       -F, --fixed-strings
		 Interpret each data-matching  pattern	as  a  list  of	 fixed
		 strings,  separated  by  newlines,  instead  of  as a regular
		 expression. What constitutes a newline for  this  purpose  is
		 controlled  by the --newline option. The -w (match as a word)
		 and -x (match whole line) options can be used with -F.	  They
		 apply to each of the fixed strings. A line is selected if any
		 of the fixed strings are found in it (subject to -w or -x, if
		 present).  This  option applies only to the patterns that are
		 matched against the contents of files; it does not  apply  to
		 patterns  specified  by  any  of  the	--include or --exclude
		 options.

       -f filename, --file=filename
		 Read patterns from the file, one per  line,  and  match  them
		 against  each	line of input. What constitutes a newline when
		 reading the file  is  the  operating  system's	 default.  The
		 --newline option has no effect on this option. Trailing white
		 space is removed from each line, and blank lines are ignored.
		 An  empty  file  contains  no	patterns and therefore matches
		 nothing. See also the comments about multiple patterns versus
		 a  single  pattern with alternatives in the description of -e
		 above.

		 If this option is given more than  once,  all	the  specified
		 files	are read. A data line is output if any of the patterns
		 match it. A filename can be given as  "-"  to	refer  to  the
		 standard  input.  When	 -f is used, patterns specified on the
		 command line using -e may also be present;  they  are	tested
		 before	 the  file's  patterns.	 However,  no other pattern is
		 taken from the command line; all arguments are treated as the
		 names of paths to be searched.

       --file-list=filename
		 Read  a  list	of  files  and/or  directories	that are to be
		 scanned from the given file, one  per	line.  Trailing	 white
		 space is removed from each line, and blank lines are ignored.
		 These paths are processed before any that are listed  on  the
		 command  line.	 The  filename can be given as "-" to refer to
		 the standard input.  If --file and --file-list are both spec‐
		 ified	as  "-",  patterns are read first. This is useful only
		 when the standard input is a  terminal,  from	which  further
		 lines	(the  list  of files) can be read after an end-of-file
		 indication. If this option is given more than once,  all  the
		 specified files are read.

       --file-offsets
		 Instead  of  showing lines or parts of lines that match, show
		 each match as an offset from the start	 of  the  file	and  a
		 length,  separated  by	 a  comma. In this mode, no context is
		 shown. That is, the -A, -B, and -C options  are  ignored.  If
		 there is more than one match in a line, each of them is shown
		 separately. This option is mutually  exclusive	 with  --line-
		 offsets and --only-matching.

       -H, --with-filename
		 Force	the  inclusion	of the filename at the start of output
		 lines when searching a single file. By default, the  filename
		 is  not  shown in this case. For matching lines, the filename
		 is followed by a colon; for context lines, a hyphen separator
		 is  used.  If	a line number is also being output, it follows
		 the file name.

       -h, --no-filename
		 Suppress the output filenames when searching multiple	files.
		 By  default,  filenames  are  shown  when  multiple files are
		 searched. For matching lines, the filename is followed	 by  a
		 colon;	 for  context lines, a hyphen separator is used.  If a
		 line number is also being output, it follows the file name.

       --help	 Output a help message, giving brief details  of  the  command
		 options  and  file type support, and then exit. Anything else
		 on the command line is ignored.

       -I	 Treat binary files as never matching. This is	equivalent  to
		 --binary-files=without-match.

       -i, --ignore-case
		 Ignore upper/lower case distinctions during comparisons.

       --include=pattern
		 If  any --include patterns are specified, the only files that
		 are processed are those that match one of the	patterns  (and
		 do  not  match	 an  --exclude	pattern). This option does not
		 affect directories, but it  applies  to  all  files,  whether
		 listed	 on the command line, obtained from --file-list, or by
		 scanning a directory. The pattern is a PCRE  regular  expres‐
		 sion,	and is matched against the final component of the file
		 name, not the entire path. The -F, -w, and -x options do  not
		 apply	to this pattern. The option may be given any number of
		 times. If a file  name	 matches  both	an  --include  and  an
		 --exclude  pattern,  it  is excluded.	There is no short form
		 for this option.

       --include-from=filename
		 Treat each non-empty line of the file	as  the	 data  for  an
		 --include option. What constitutes a newline for this purpose
		 is the operating system's default. The --newline  option  has
		 no effect on this option. This option may be given any number
		 of times; all the files are read.

       --include-dir=pattern
		 If any --include-dir patterns are specified, the only	direc‐
		 tories	 that  are  processed  are those that match one of the
		 patterns (and do not match an	--exclude-dir  pattern).  This
		 applies  to  all  directories,	 whether listed on the command
		 line, obtained from --file-list,  or  by  scanning  a	parent
		 directory.  The  pattern is a PCRE regular expression, and is
		 matched against the final component of	 the  directory	 name,
		 not  the entire path. The -F, -w, and -x options do not apply
		 to this pattern. The option may be given any number of times.
		 If  a directory matches both --include-dir and --exclude-dir,
		 it is excluded. There is no short form for this option.

       -L, --files-without-match
		 Instead of outputting lines from the files, just  output  the
		 names	of  the files that do not contain any lines that would
		 have been output. Each file name is output once, on  a	 sepa‐
		 rate line.

       -l, --files-with-matches
		 Instead  of  outputting lines from the files, just output the
		 names of the files containing lines that would have been out‐
		 put.  Each  file  name	 is  output  once, on a separate line.
		 Searching normally stops as soon as a matching line is	 found
		 in  a	file.  However, if the -c (count) option is also used,
		 matching continues in order to obtain the correct count,  and
		 those	files  that  have  at least one match are listed along
		 with their counts. Using this option with -c is a way of sup‐
		 pressing the listing of files with no matches.

       --label=name
		 This option supplies a name to be used for the standard input
		 when file names are being output. If not supplied, "(standard
		 input)" is used. There is no short form for this option.

       --line-buffered
		 When  this  option is given, input is read and processed line
		 by line, and the output  is  flushed  after  each  write.  By
		 default,  input  is read in large chunks, unless pcregrep can
		 determine that it is reading from a terminal (which  is  cur‐
		 rently	 possible  only	 in Unix-like environments). Output to
		 terminal is normally automatically flushed by	the  operating
		 system. This option can be useful when the input or output is
		 attached to a pipe and you do not want pcregrep to buffer  up
		 large	amounts	 of data. However, its use will affect perfor‐
		 mance, and the -M (multiline) option ceases to work.

       --line-offsets
		 Instead of showing lines or parts of lines that  match,  show
		 each match as a line number, the offset from the start of the
		 line, and a length. The line number is terminated by a	 colon
		 (as  usual; see the -n option), and the offset and length are
		 separated by a comma. In this	mode,  no  context  is	shown.
		 That  is, the -A, -B, and -C options are ignored. If there is
		 more than one match in a line, each of them  is  shown	 sepa‐
		 rately. This option is mutually exclusive with --file-offsets
		 and --only-matching.

       --locale=locale-name
		 This option specifies a locale to be used for pattern	match‐
		 ing.  It  overrides the value in the LC_ALL or LC_CTYPE envi‐
		 ronment variables.  If	 no  locale  is	 specified,  the  PCRE
		 library's  default (usually the "C" locale) is used. There is
		 no short form for this option.

       --match-limit=number
		 Processing some regular expression  patterns  can  require  a
		 very  large amount of memory, leading in some cases to a pro‐
		 gram crash if not enough is available.	  Other	 patterns  may
		 take  a  very	long  time to search for all possible matching
		 strings. The pcre_exec() function that is called by  pcregrep
		 to  do	 the  matching	has  two parameters that can limit the
		 resources that it uses.

		 The  --match-limit  option  provides  a  means	 of   limiting
		 resource usage when processing patterns that are not going to
		 match, but which have a very large number of possibilities in
		 their	search	trees.	The  classic example is a pattern that
		 uses nested unlimited repeats. Internally, PCRE uses a	 func‐
		 tion  called  match()	which  it  calls repeatedly (sometimes
		 recursively). The limit set by --match-limit  is  imposed  on
		 the  number  of times this function is called during a match,
		 which has the effect of limiting the amount  of  backtracking
		 that can take place.

		 The --recursion-limit option is similar to --match-limit, but
		 instead of limiting the total number of times that match() is
		 called, it limits the depth of recursive calls, which in turn
		 limits the amount of memory that can be used.	The  recursion
		 depth	is  a  smaller	number than the total number of calls,
		 because not all calls to match() are recursive. This limit is
		 of use only if it is set smaller than --match-limit.

		 There	are no short forms for these options. The default set‐
		 tings are specified when the PCRE library is  compiled,  with
		 the default default being 10 million.

       -M, --multiline
		 Allow	patterns to match more than one line. When this option
		 is given, patterns may usefully contain literal newline char‐
		 acters	 and  internal	occurrences of ^ and $ characters. The
		 output for a successful match may consist of  more  than  one
		 line,	the last of which is the one in which the match ended.
		 If the matched string ends with a newline sequence the output
		 ends at the end of that line.

		 When  this option is set, the PCRE library is called in "mul‐
		 tiline" mode.	There is a limit to the number of  lines  that
		 can  be matched, imposed by the way that pcregrep buffers the
		 input file as it scans it. However, pcregrep ensures that  at
		 least 8K characters or the rest of the document (whichever is
		 the shorter) are available for forward	 matching,  and	 simi‐
		 larly the previous 8K characters (or all the previous charac‐
		 ters, if fewer than 8K) are guaranteed to  be	available  for
		 lookbehind  assertions.  This option does not work when input
		 is read line by line (see --line-buffered.)

       -N newline-type, --newline=newline-type
		 The PCRE library  supports  five  different  conventions  for
		 indicating  the  ends of lines. They are the single-character
		 sequences CR (carriage return) and LF	(linefeed),  the  two-
		 character  sequence CRLF, an "anycrlf" convention, which rec‐
		 ognizes any of the preceding three types, and an  "any"  con‐
		 vention, in which any Unicode line ending sequence is assumed
		 to end a line. The Unicode sequences are the three just  men‐
		 tioned,  plus	VT  (vertical  tab,  U+000B),  FF  (form feed,
		 U+000C),  NEL	(next  line,  U+0085),	LS  (line   separator,
		 U+2028), and PS (paragraph separator, U+2029).

		 When  the  PCRE  library  is  built,  a  default  line-ending
		 sequence  is  specified.   This  is  normally	the   standard
		 sequence for the operating system. Unless otherwise specified
		 by this option, pcregrep uses	the  library's	default.   The
		 possible values for this option are CR, LF, CRLF, ANYCRLF, or
		 ANY. This makes it possible to use  pcregrep  to  scan	 files
		 that have come from other environments without having to mod‐
		 ify their line endings. If the data  that  is	being  scanned
		 does  not agree with the convention set by this option, pcre‐
		 grep may behave in strange ways. Note that this  option  does
		 not  apply  to	 files specified by the -f, --exclude-from, or
		 --include-from options, which are expected to use the operat‐
		 ing system's standard newline sequence.

       -n, --line-number
		 Precede each output line by its line number in the file, fol‐
		 lowed by a colon for matching lines or a hyphen  for  context
		 lines.	 If the filename is also being output, it precedes the
		 line number. This option is forced if --line-offsets is used.

       --no-jit	 If the PCRE library is built with  support  for  just-in-time
		 compiling  (which speeds up matching), pcregrep automatically
		 makes use of this, unless it was explicitly disabled at build
		 time.	This  option  can be used to disable the use of JIT at
		 run time. It is provided for testing and working round	 prob‐
		 lems.	It should never be needed in normal use.

       -o, --only-matching
		 Show only the part of the line that matched a pattern instead
		 of the whole line. In this mode, no context  is  shown.  That
		 is,  the -A, -B, and -C options are ignored. If there is more
		 than one match in a line, each of them is  shown  separately.
		 If  -o	 is combined with -v (invert the sense of the match to
		 find non-matching lines), no output  is  generated,  but  the
		 return	 code  is set appropriately. If the matched portion of
		 the line is empty, nothing is output unless the file name  or
		 line  number  are being printed, in which case they are shown
		 on an otherwise empty line. This option is mutually exclusive
		 with --file-offsets and --line-offsets.

       -onumber, --only-matching=number
		 Show  only  the  part	of the line that matched the capturing
		 parentheses of the given number. Up to 32 capturing parenthe‐
		 ses are supported, and -o0 is equivalent to -o without a num‐
		 ber. Because these options can be given without  an  argument
		 (see  above),	if an argument is present, it must be given in
		 the same shell item, for example, -o3	or  --only-matching=2.
		 The comments given for the non-argument case above also apply
		 to this case. If the specified capturing parentheses  do  not
		 exist	in  the pattern, or were not set in the match, nothing
		 is output unless the file  name  or  line  number  are	 being
		 printed.

		 If  this  option is given multiple times, multiple substrings
		 are output, in the order the options are given. For  example,
		 -o3 -o1 -o3 causes the substrings matched by capturing paren‐
		 theses 3 and 1 and then 3 again to  be	 output.  By  default,
		 there is no separator (but see the next option).

       --om-separator=text
		 Specify  a  separating string for multiple occurrences of -o.
		 The default is an empty string. Separating strings are	 never
		 coloured.

       -q, --quiet
		 Work quietly, that is, display nothing except error messages.
		 The exit status indicates whether or  not  any	 matches  were
		 found.

       -r, --recursive
		 If  any given path is a directory, recursively scan the files
		 it contains, taking note of any --include and --exclude  set‐
		 tings.	 By  default, a directory is read as a normal file; in
		 some operating systems this gives an  immediate  end-of-file.
		 This  option  is  a  shorthand	 for  setting the -d option to
		 "recurse".

       --recursion-limit=number
		 See --match-limit above.

       -s, --no-messages
		 Suppress error	 messages  about  non-existent	or  unreadable
		 files.	 Such  files  are quietly skipped. However, the return
		 code is still 2, even if matches were found in other files.

       -u, --utf-8
		 Operate in UTF-8 mode. This option is available only if  PCRE
		 has been compiled with UTF-8 support. All patterns (including
		 those for any --exclude and --include options) and  all  sub‐
		 ject  lines  that  are scanned must be valid strings of UTF-8
		 characters.

       -V, --version
		 Write the version numbers of pcregrep and the PCRE library to
		 the  standard output and then exit. Anything else on the com‐
		 mand line is ignored.

       -v, --invert-match
		 Invert the sense of the match, so that	 lines	which  do  not
		 match any of the patterns are the ones that are found.

       -w, --word-regex, --word-regexp
		 Force the patterns to match only whole words. This is equiva‐
		 lent to having \b at the start and end of the	pattern.  This
		 option	 applies only to the patterns that are matched against
		 the contents of files; it does not apply to  patterns	speci‐
		 fied by any of the --include or --exclude options.

       -x, --line-regex, --line-regexp
		 Force	the  patterns to be anchored (each must start matching
		 at the beginning of a line) and in addition, require them  to
		 match	entire	lines.	This  is  equivalent to having ^ and $
		 characters at the start and end of each alternative branch in
		 every	pattern. This option applies only to the patterns that
		 are matched against the contents of files; it does not	 apply
		 to  patterns  specified  by any of the --include or --exclude
		 options.

ENVIRONMENT VARIABLES

       The environment variables LC_ALL and LC_CTYPE  are  examined,  in  that
       order,  for  a  locale.	The first one that is set is used. This can be
       overridden by the --locale option.  If  no  locale  is  set,  the  PCRE
       library's default (usually the "C" locale) is used.

NEWLINES

       The  -N (--newline) option allows pcregrep to scan files with different
       newline conventions from the default. Any parts of the input files that
       are  written  to the standard output are copied identically, with what‐
       ever newline sequences they have in the input. However, the setting  of
       this  option  does  not affect the interpretation of files specified by
       the -f, --exclude-from, or --include-from options, which are assumed to
       use  the	 operating  system's  standard	newline	 sequence, nor does it
       affect the way in which pcregrep writes informational messages  to  the
       standard error and output streams. For these it uses the string "\n" to
       indicate newlines, relying on the C I/O library to convert this	to  an
       appropriate sequence.

OPTIONS COMPATIBILITY

       Many  of the short and long forms of pcregrep's options are the same as
       in the GNU grep program. Any long option of the form --xxx-regexp  (GNU
       terminology)  is also available as --xxx-regex (PCRE terminology). How‐
       ever, the --file-list, --file-offsets,  --include-dir,  --line-offsets,
       --locale,  --match-limit,  -M, --multiline, -N, --newline, --om-separa‐
       tor, --recursion-limit, -u, and --utf-8 options are specific  to	 pcre‐
       grep,  as  is  the  use	of the --only-matching option with a capturing
       parentheses number.

       Although most of the common options work the same way, a few  are  dif‐
       ferent  in  pcregrep. For example, the --include option's argument is a
       glob for GNU grep, but a regular expression for pcregrep. If  both  the
       -c  and	-l  options are given, GNU grep lists only file names, without
       counts, but pcregrep gives the counts.

OPTIONS WITH DATA

       There are four different ways in which an option with data can be spec‐
       ified.	If  a  short  form option is used, the data may follow immedi‐
       ately, or (with one exception) in the next command line item. For exam‐
       ple:

	 -f/some/file
	 -f /some/file

       The  exception is the -o option, which may appear with or without data.
       Because of this, if data is present, it must follow immediately in  the
       same item, for example -o3.

       If  a long form option is used, the data may appear in the same command
       line item, separated by an equals character, or (with  two  exceptions)
       it may appear in the next command line item. For example:

	 --file=/some/file
	 --file /some/file

       Note,  however, that if you want to supply a file name beginning with ~
       as data in a shell command, and have the	 shell	expand	~  to  a  home
       directory, you must separate the file name from the option, because the
       shell does not treat ~ specially unless it is at the start of an item.

       The exceptions to the above are the --colour (or --color)  and  --only-
       matching	 options,  for	which  the  data  is optional. If one of these
       options does have data, it must be given in the first  form,  using  an
       equals character. Otherwise pcregrep will assume that it has no data.

MATCHING ERRORS

       It  is  possible	 to supply a regular expression that takes a very long
       time to fail to match certain lines.  Such  patterns  normally  involve
       nested  indefinite repeats, for example: (a+)*\d when matched against a
       line of a's with no final digit.	 The  PCRE  matching  function	has  a
       resource	 limit that causes it to abort in these circumstances. If this
       happens, pcregrep outputs an error message and the line that caused the
       problem	to  the	 standard error stream. If there are more than 20 such
       errors, pcregrep gives up.

       The --match-limit option of pcregrep can be used	 to  set  the  overall
       resource	 limit; there is a second option called --recursion-limit that
       sets a limit on the amount of memory (usually stack) that is used  (see
       the discussion of these options above).

DIAGNOSTICS

       Exit status is 0 if any matches were found, 1 if no matches were found,
       and 2 for syntax errors, overlong lines, non-existent  or  inaccessible
       files  (even if matches were found in other files) or too many matching
       errors. Using the -s option to suppress error messages about inaccessi‐
       ble files does not affect the return code.

SEE ALSO

       pcrepattern(3), pcresyntax(3), pcretest(1).

AUTHOR

       Philip Hazel
       University Computing Service
       Cambridge CB2 3QH, England.

REVISION

       Last updated: 13 September 2012
       Copyright (c) 1997-2012 University of Cambridge.

PCRE 8.32		       13 September 2012		   PCREGREP(1)
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