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PCRETEST(1)		    General Commands Manual		   PCRETEST(1)

       pcretest	- a program for	testing	Perl-compatible	regular	expressions.

       pcretest	[options] [input file [output file]]

       pcretest	 was written as	a test program for the PCRE regular expression
       library itself, but it can also be used for experimenting with  regular
       expressions.  This document describes the features of the test program;
       for details of the regular expressions themselves, see the  pcrepattern
       documentation. For details of the PCRE library function calls and their
       options,	see the	pcreapi	, pcre16 and pcre32 documentation.

       The input for pcretest is a sequence of regular expression patterns and
       strings	to be matched, as described below. The output shows the	result
       of each match. Options on the command line  and	the  patterns  control
       PCRE options and	exactly	what is	output.

       As  PCRE	has evolved, it	has acquired many different features, and as a
       result, pcretest	now has	rather a lot of	obscure	 options  for  testing
       every possible feature. Some of these options are specifically designed
       for use in conjunction with the test script and	data  files  that  are
       distributed  as	part of	PCRE, and are unlikely to be of	use otherwise.
       They are	all documented here, but without much justification.

       Input to	pcretest is processed line by line, either by  calling	the  C
       library's fgets() function, or via the libreadline library (see below).
       In Unix-like environments, fgets() treats any bytes other than  newline
       as  data	characters. However, in	some Windows environments character 26
       (hex 1A)	causes an immediate end	of file, and no	further	data is	 read.
       For  maximum  portability,  therefore,  it  is safest to	use only ASCII
       characters in pcretest input files.

       From release 8.30, two separate PCRE libraries can be built. The	origi-
       nal  one	supports 8-bit character strings, whereas the newer 16-bit li-
       brary supports character	strings	encoded	in 16-bit units. From  release
       8.32,  a	 third	library	can be built, supporting character strings en-
       coded in	32-bit units. The pcretest program can be  used	 to  test  all
       three  libraries. However, it is	itself still an	8-bit program, reading
       8-bit input and writing 8-bit  output.	When  testing  the  16-bit  or
       32-bit  library,	 the patterns and data strings are converted to	16- or
       32-bit format before being passed to the	PCRE  library  functions.  Re-
       sults are converted to 8-bit for	output.

       References to functions and structures of the form pcre[16|32]_xx below
       mean "pcre_xx when using	the 8-bit library, pcre16_xx  when  using  the
       16-bit library, or pcre32_xx when using the 32-bit library".

       -8	 If  both the 8-bit library has	been built, this option	causes
		 the 8-bit library to be used (which is	the default);  if  the
		 8-bit	library	 has not been built, this option causes	an er-

       -16	 If both the 8-bit or the 32-bit,  and	the  16-bit  libraries
		 have  been built, this	option causes the 16-bit library to be
		 used. If only the 16-bit library has been built, this is  the
		 default  (so  has no effect). If only the 8-bit or the	32-bit
		 library has been built, this option causes an error.

       -32	 If both the 8-bit or the 16-bit,  and	the  32-bit  libraries
		 have  been built, this	option causes the 32-bit library to be
		 used. If only the 32-bit library has been built, this is  the
		 default  (so  has no effect). If only the 8-bit or the	16-bit
		 library has been built, this option causes an error.

       -b	 Behave	as if each pattern has the /B (show byte  code)	 modi-
		 fier; the internal form is output after compilation.

       -C	 Output	the version number of the PCRE library,	and all	avail-
		 able information about	the optional  features	that  are  in-
		 cluded,  and then exit	with zero exit code. All other options
		 are ignored.

       -C option Output	information about a specific build-time	 option,  then
		 exit.	This functionality is intended for use in scripts such
		 as RunTest. The following options output the  value  and  set
		 the exit code as indicated:

		   ebcdic-nl  the code for LF (= NL) in	an EBCDIC environment:
				0x15 or	0x25
				0 if used in an	ASCII environment
				exit code is always 0
		   linksize   the configured internal link size	(2, 3, or 4)
				exit code is set to the	link size
		   newline    the default newline setting:
				exit code is always 0
		   bsr	      the default setting for what \R matches:
				exit code is always 0

		 The  following	 options output	1 for true or 0	for false, and
		 set the exit code to the same value:

		   ebcdic     compiled for an EBCDIC environment
		   jit	      just-in-time support is available
		   pcre16     the 16-bit library was built
		   pcre32     the 32-bit library was built
		   pcre8      the 8-bit	library	was built
		   ucp	      Unicode property support is available
		   utf	      UTF-8 and/or UTF-16 and/or UTF-32	support
				is available

		 If an unknown option is given,	an error  message  is  output;
		 the exit code is 0.

       -d	 Behave	 as  if	 each pattern has the /D (debug) modifier; the
		 internal form and information about the compiled  pattern  is
		 output	after compilation; -d is equivalent to -b -i.

       -dfa	 Behave	 as if each data line contains the \D escape sequence;
		 this	 causes	   the	  alternative	 matching    function,
		 pcre[16|32]_dfa_exec(),  to  be  used instead of the standard
		 pcre[16|32]_exec() function (more detail is given below).

       -help	 Output	a brief	summary	these options and then exit.

       -i	 Behave	as if each pattern has the  /I	modifier;  information
		 about the compiled pattern is given after compilation.

       -M	 Behave	 as if each data line contains the \M escape sequence;
		 this causes PCRE to  discover	the  minimum  MATCH_LIMIT  and
		 MATCH_LIMIT_RECURSION	settings by calling pcre[16|32]_exec()
		 repeatedly with different limits.

       -m	 Output	the size of each compiled pattern after	 it  has  been
		 compiled. This	is equivalent to adding	/M to each regular ex-
		 pression. The size is given in	bytes for both libraries.

       -O	 Behave	as if each pattern has the /O modifier,	that  is  dis-
		 able auto-possessification for	all patterns.

       -o osize	 Set  the number of elements in	the output vector that is used
		 when calling pcre[16|32]_exec() or pcre[16|32]_dfa_exec()  to
		 be  osize.  The  default  value is 45,	which is enough	for 14
		 capturing subexpressions for pcre[16|32]_exec() or 22 differ-
		 ent  matches for pcre[16|32]_dfa_exec().  The vector size can
		 be changed for	individual matching calls by including	\O  in
		 the data line (see below).

       -p	 Behave	 as  if	 each  pattern	has the	/P modifier; the POSIX
		 wrapper API is	used to	call PCRE. None	of the	other  options
		 has  any  effect when -p is set. This option can be used only
		 with the 8-bit	library.

       -q	 Do not	output the version number of pcretest at the start  of

       -S size	 On  Unix-like	systems, set the size of the run-time stack to
		 size megabytes.

       -s or -s+ Behave	as if each pattern  has	 the  /S  modifier;  in	 other
		 words,	 force each pattern to be studied. If -s+ is used, all
		 the JIT compile options are  passed  to  pcre[16|32]_study(),
		 causing  just-in-time	optimization  to  be  set  up if it is
		 available, for	both full and partial matching.	 Specific  JIT
		 compile options can be	selected by following -s+ with a digit
		 in the	range 1	to 7, which selects the	JIT compile  modes  as

		   1  normal match only
		   2  soft partial match only
		   3  normal match and soft partial match
		   4  hard partial match only
		   6  soft and hard partial match
		   7  all three	modes (default)

		 If  -s++  is used instead of -s+ (with	or without a following
		 digit), the text "(JIT)" is added to the  first  output  line
		 after a match or no match when	JIT-compiled code was actually

		 Note that there are pattern options that can override -s, ei-
		 ther specifying no studying at	all, or	suppressing JIT	compi-

		 If the	/I or /D option	is present on  a  pattern  (requesting
		 output	about the compiled pattern), information about the re-
		 sult of studying is not included when studying	is caused only
		 by  -s	 and neither -i	nor -d is present on the command line.
		 This behaviour	means that the output from tests that are  run
		 with  and without -s should be	identical, except when options
		 that output information about the actual running of  a	 match
		 are set.

		 The -M, -t, and -tm options, which give information about re-
		 sources used, are likely to produce different output with and
		 without  -s.  Output  may  also  differ  if  the /C option is
		 present on an individual pattern. This	uses callouts to trace
		 the  the  matching process, and this may be different between
		 studied and non-studied patterns.  If	the  pattern  contains
		 (*MARK)  items	 there	may  also be differences, for the same
		 reason. The -s	command	line option can	be overridden for spe-
		 cific	patterns that should never be studied (see the /S pat-
		 tern modifier below).

       -t	 Run each compile, study, and match many times with  a	timer,
		 and  output  the resulting times per compile, study, or match
		 (in milliseconds). Do not set -m with -t,  because  you  will
		 then get the size output a zillion times, and the timing will
		 be distorted. You can control the number of  iterations  that
		 are used for timing by	following -t with a number (as a sepa-
		 rate item on the command line). For example, "-t 1000"	 iter-
		 ates 1000 times.  The default is to iterate 500000 times.

       -tm	 This is like -t except	that it	times only the matching	phase,
		 not the compile or study phases.

       -T -TM	 These behave like -t and -tm, but in addition,	at the end  of
		 a run,	the total times	for all	compiles, studies, and matches
		 are output.

       If pcretest is given two	filename arguments, it reads  from  the	 first
       and writes to the second. If it is given	only one filename argument, it
       reads from that file and	writes to stdout.  Otherwise,  it  reads  from
       stdin  and  writes to stdout, and prompts for each line of input, using
       "re>" to	prompt for regular expressions,	and "data>" to prompt for data

       When  pcretest  is  built,  a  configuration option can specify that it
       should be linked	with the libreadline library. When this	 is  done,  if
       the input is from a terminal, it	is read	using the readline() function.
       This provides line-editing and history facilities. The output from  the
       -help option states whether or not readline() will be used.

       The program handles any number of sets of input on a single input file.
       Each set	starts with a regular expression, and continues	with any  num-
       ber of data lines to be matched against that pattern.

       Each  data line is matched separately and independently.	If you want to
       do multi-line matches, you have to use the \n escape sequence (or \r or
       \r\n, etc., depending on	the newline setting) in	a single line of input
       to encode the newline sequences.	There is no limit  on  the  length  of
       data  lines;  the  input	 buffer	is automatically extended if it	is too

       An empty	line signals the end of	the data lines,	at which point	a  new
       regular	expression is read. The	regular	expressions are	given enclosed
       in any non-alphanumeric delimiters other	than backslash,	for example:


       White space before the initial delimiter	is ignored. A regular  expres-
       sion  may be continued over several input lines,	in which case the new-
       line characters are included within it. It is possible to  include  the
       delimiter within	the pattern by escaping	it, for	example


       If  you	do  so,	the escape and the delimiter form part of the pattern,
       but since delimiters are	always non-alphanumeric, this does not	affect
       its  interpretation.   If the terminating delimiter is immediately fol-
       lowed by	a backslash, for example,


       then a backslash	is added to the	end of the pattern. This  is  done  to
       provide	a  way of testing the error condition that arises if a pattern
       finishes	with a backslash, because


       is interpreted as the first line	of a pattern that starts with  "abc/",
       causing pcretest	to read	the next line as a continuation	of the regular

       A pattern may be	followed by any	number of modifiers, which are	mostly
       single  characters,  though  some  of these can be qualified by further
       characters.  Following Perl usage, these	are referred to	below as,  for
       example,	 "the  /i  modifier", even though the delimiter	of the pattern
       need not	always be a slash, and no slash	is  used  when	writing	 modi-
       fiers.  White  space may	appear between the final pattern delimiter and
       the first modifier, and between the modifiers  themselves.  For	refer-
       ence,  here  is	a  complete  list of modifiers.	They fall into several
       groups that are described in detail in the following sections.

	 /8		 set UTF mode
	 /9		 set PCRE_NEVER_UTF (locks out UTF mode)
	 /?		 disable UTF validity check
	 /+		 show remainder	of subject after match
	 /=		 show all captures (not	just those that	are set)

	 /B		 show compiled code
	 /D		 same as /B plus /I
	 /F		 flip byte order in compiled pattern
	 /G		 find all matches (shorten string)
	 /g		 find all matches (use startoffset)
	 /I		 show information about	pattern
	 /i		 set PCRE_CASELESS
	 /K		 show backtracking control names
	 /L		 set locale
	 /M		 show compiled memory size
	 /P		 use the POSIX wrapper
	 /Q		 test external stack check function
	 /S		 study the pattern after compilation
	 /s		 set PCRE_DOTALL
	 /T		 select	character tables
	 /W		 set PCRE_UCP
	 /X		 set PCRE_EXTRA
	 /x		 set PCRE_EXTENDED
	 /Z		 don't show lengths in /B output

	 /<any>		 set PCRE_NEWLINE_ANY
	 /<anycrlf>	 set PCRE_NEWLINE_ANYCRLF
	 /<cr>		 set PCRE_NEWLINE_CR
	 /<crlf>	 set PCRE_NEWLINE_CRLF
	 /<lf>		 set PCRE_NEWLINE_LF
	 /<bsr_anycrlf>	 set PCRE_BSR_ANYCRLF
	 /<bsr_unicode>	 set PCRE_BSR_UNICODE

   Perl-compatible modifiers
       The /i, /m, /s, and /x modifiers	set the	PCRE_CASELESS, PCRE_MULTILINE,
       PCRE_DOTALL,    or    PCRE_EXTENDED    options,	  respectively,	  when
       pcre[16|32]_compile() is	called.	These four modifier letters  have  the
       same effect as they do in Perl. For example:


   Modifiers for other PCRE options
       The  following  table  shows additional modifiers for setting PCRE com-
       pile-time options that do not correspond	to anything in Perl:

	 /8		 PCRE_UTF8	     ) when using the 8-bit
	 /?		 PCRE_NO_UTF8_CHECK  )	 library

	 /8		 PCRE_UTF16	     ) when using the 16-bit
	 /?		 PCRE_NO_UTF16_CHECK )	 library

	 /8		 PCRE_UTF32	     ) when using the 32-bit
	 /?		 PCRE_NO_UTF32_CHECK )	 library

	 /<bsr_anycrlf>	 PCRE_BSR_ANYCRLF
	 /<bsr_unicode>	 PCRE_BSR_UNICODE

       The modifiers that are enclosed in angle	brackets are  literal  strings
       as  shown,  including the angle brackets, but the letters within	can be
       in either case.	This example sets multiline matching with CRLF as  the
       line ending sequence:


       As  well	 as  turning  on  the  PCRE_UTF8/16/32 option, the /8 modifier
       causes all non-printing characters in output strings to be printed  us-
       ing the \x{hh...} notation. Otherwise, those less than 0x100 are	output
       in hex without the curly	brackets.

       Full details of the PCRE	options	are given in  the  pcreapi  documenta-

   Finding all matches in a string
       Searching  for  all  possible matches within each subject string	can be
       requested by the	/g or /G modifier. After  finding  a  match,  PCRE  is
       called again to search the remainder of the subject string. The differ-
       ence between /g and /G is that the former uses the startoffset argument
       to  pcre[16|32]_exec() to start searching at a new point	within the en-
       tire string (which is in	effect what Perl  does),  whereas  the	latter
       passes  over  a	shortened  substring.  This  makes a difference	to the
       matching	process	if the pattern begins with a lookbehind	assertion (in-
       cluding \b or \B).

       If  any	call  to  pcre[16|32]_exec() in	a /g or	/G sequence matches an
       empty string, the next call is done with	the PCRE_NOTEMPTY_ATSTART  and
       PCRE_ANCHORED  flags  set  in  order  to	search for another, non-empty,
       match at	the same point.	If this	second match fails, the	 start	offset
       is  advanced,  and  the	normal match is	retried. This imitates the way
       Perl handles such cases when using the /g modifier or the split() func-
       tion.  Normally,	 the start offset is advanced by one character,	but if
       the newline convention recognizes CRLF as a newline,  and  the  current
       character is CR followed	by LF, an advance of two is used.

   Other modifiers
       There are yet more modifiers for	controlling the	way pcretest operates.

       The  /+ modifier	requests that as well as outputting the	substring that
       matched the entire pattern, pcretest should in addition output the  re-
       mainder	of the subject string. This is useful for tests	where the sub-
       ject contains multiple copies of	the same substring. If the +  modifier
       appears	twice,	the  same  action is taken for captured	substrings. In
       each case the remainder is output on the	following  line	 with  a  plus
       character  following  the  capture number. Note that this modifier must
       not immediately follow the /S modifier because /S+ and /S++ have	 other

       The  /=	modifier  requests  that  the values of	all potential captured
       parentheses be output after a match. By default,	only those up  to  the
       highest one actually used in the	match are output (corresponding	to the
       return code from	pcre[16|32]_exec()). Values in the offsets vector cor-
       responding  to higher numbers should be set to -1, and these are	output
       as "<unset>". This modifier gives a way of checking that	this  is  hap-

       The  /B modifier	is a debugging feature.	It requests that pcretest out-
       put a representation of the compiled code after	compilation.  Normally
       this  information  contains length and offset values; however, if /Z is
       also present, this data is replaced by spaces. This is a	 special  fea-
       ture  for  use  in the automatic	test scripts; it ensures that the same
       output is generated for different internal link sizes.

       The /D modifier is a PCRE debugging feature, and	is equivalent to  /BI,
       that is,	both the /B and	the /I modifiers.

       The  /F	modifier  causes pcretest to flip the byte order of the	2-byte
       and 4-byte fields in the	compiled pattern. This facility	is for testing
       the  feature  in	PCRE that allows it to execute patterns	that were com-
       piled on	a host with a different	endianness. This feature is not	avail-
       able  when the POSIX interface to PCRE is being used, that is, when the
       /P pattern modifier is specified. See also the section about saving and
       reloading compiled patterns below.

       The  /I	modifier  requests  that pcretest output information about the
       compiled	pattern	(whether it is anchored, has a fixed first  character,
       and  so	on). It	does this by calling pcre[16|32]_fullinfo() after com-
       piling a	pattern. If the	pattern	is studied, the	results	 of  that  are
       also output. In this output, the	word "char" means a non-UTF character,
       that is,	the value of a single data item	(8-bit,	16-bit,	or 32-bit, de-
       pending on the library that is being tested).

       The  /K modifier	requests pcretest to show names	from backtracking con-
       trol verbs that are  returned  from  calls  to  pcre[16|32]_exec().  It
       causes  pcretest	to create a pcre[16|32]_extra block if one has not al-
       ready been created by a call to pcre[16|32]_study(),  and  to  set  the
       PCRE_EXTRA_MARK	flag  and  the	mark  field within it, every time that
       pcre[16|32]_exec() is called. If	 the  variable	that  the  mark	 field
       points  to  is  non-NULL	 for  a	 match,	 non-match,  or	partial	match,
       pcretest	prints the string to which it points. For  a  match,  this  is
       shown  on  a  line  by itself, tagged with "MK:". For a non-match it is
       added to	the message.

       The /L modifier must be followed	directly by the	name of	a locale,  for


       For this	reason,	it must	be the last modifier. The given	locale is set,
       pcre[16|32]_maketables()	is called to build a set of  character	tables
       for  the	 locale, and this is then passed to pcre[16|32]_compile() when
       compiling the regular expression. Without an /L (or /T) modifier,  NULL
       is  passed  as  the tables pointer; that	is, /L applies only to the ex-
       pression	on which it appears.

       The /M modifier causes the size in bytes	of the memory  block  used  to
       hold  the compiled pattern to be	output.	This does not include the size
       of the pcre[16|32] block; it is just the	actual compiled	data.  If  the
       pattern is successfully studied with the	PCRE_STUDY_JIT_COMPILE option,
       the size	of the JIT compiled code is also output.

       The /Q modifier is used to test the use of pcre_stack_guard. It must be
       followed	 by '0'	or '1',	specifying the return code to be given from an
       external	function that is passed	to PCRE	and used  for  stack  checking
       during compilation (see the pcreapi documentation for details).

       The  /S	modifier causes	pcre[16|32]_study() to be called after the ex-
       pression	has been compiled, and the results used	when the expression is
       matched.	 There	are  a number of qualifying characters that may	follow
       /S.  They may appear in any order.

       If /S is	followed by an exclamation mark, pcre[16|32]_study() is	called
       with  the PCRE_STUDY_EXTRA_NEEDED option, causing it always to return a
       pcre_extra block, even when studying discovers no useful	information.

       If /S is	followed by a second S character, it suppresses	studying, even
       if  it  was  requested  externally  by the -s command line option. This
       makes it	possible to specify that certain patterns are always  studied,
       and others are never studied, independently of -s. This feature is used
       in the test files in a few cases	where the output is different when the
       pattern is studied.

       If  the	/S  modifier  is  followed  by	a  +  character,  the  call to
       pcre[16|32]_study() is made with	all the	JIT study options,  requesting
       just-in-time  optimization  support if it is available, for both	normal
       and partial matching. If	you want to restrict the JIT compiling	modes,
       you can follow /S+ with a digit in the range 1 to 7:

	 1  normal match only
	 2  soft partial match only
	 3  normal match and soft partial match
	 4  hard partial match only
	 6  soft and hard partial match
	 7  all	three modes (default)

       If /S++ is used instead of /S+ (with or without a following digit), the
       text "(JIT)" is added to	the first output line  after  a	 match	or  no
       match when JIT-compiled code was	actually used.

       Note  that  there  is  also  an independent /+ modifier;	it must	not be
       given immediately after /S or /S+ because this will be misinterpreted.

       If JIT studying is successful, the compiled JIT code will automatically
       be  used	 when pcre[16|32]_exec() is run, except	when incompatible run-
       time options are	specified. For more details, see the pcrejit  documen-
       tation.	See also the \J	escape sequence	below for a way	of setting the
       size of the JIT stack.

       Finally,	if /S is followed by a minus  character,  JIT  compilation  is
       suppressed,  even if it was requested externally	by the -s command line
       option. This makes it possible to specify that JIT is never to be  used
       for certain patterns.

       The  /T	modifier  must be followed by a	single digit. It causes	a spe-
       cific set of built-in character tables to be passed to pcre[16|32]_com-
       pile().	It  is used in the standard PCRE tests to check	behaviour with
       different character tables. The digit specifies the tables as follows:

	 0   the default ASCII tables, as distributed in
	 1   a set of tables defining ISO 8859 characters

       In table	1, some	characters whose codes are greater than	128 are	 iden-
       tified as letters, digits, spaces, etc.

   Using the POSIX wrapper API
       The  /P modifier	causes pcretest	to call	PCRE via the POSIX wrapper API
       rather than its native API. This	supports only the 8-bit	library.  When
       /P  is set, the following modifiers set options for the regcomp() func-

	 /i    REG_ICASE
	 /s    REG_DOTALL     )
	 /U    REG_UNGREEDY   )	These options are not part of
	 /W    REG_UCP	      )	  the POSIX standard
	 /8    REG_UTF8	      )

       The /+ modifier works as	described above. All other modifiers  are  ig-

   Locking out certain modifiers
       PCRE  can be compiled with or without support for certain features such
       as UTF-8/16/32 or Unicode properties. Accordingly, the  standard	 tests
       are  split  up  into  a number of different files that are selected for
       running depending on which features are available.  When	 updating  the
       tests, it is all	too easy to put	a new test into	the wrong file by mis-
       take; for example, to put a test	that requires UTF support into a  file
       that  is	used when it is	not available. To help detect such mistakes as
       early as	possible, there	is a facility for locking out  specific	 modi-
       fiers. If an input line for pcretest starts with	the string "< forbid "
       the following sequence of characters is taken as	a  list	 of  forbidden
       modifiers. For example, in the test files that must not use UTF or Uni-
       code property support, this line	appears:

	 < forbid 8W

       This locks out the /8 and /W modifiers. An immediate error is given  if
       they  are  subsequently encountered. If the character string contains <
       but not >, all the multi-character modifiers  that  begin  with	<  are
       locked  out.  Otherwise,	 such modifiers	must be	explicitly listed, for

	 < forbid <JS><cr>

       There must be a single space between < and "forbid" for this feature to
       be recognised. If there is not, the line	is interpreted either as a re-
       quest to	re-load	a pre-compiled pattern (see "SAVING AND	RELOADING COM-
       PILED PATTERNS" below) or, if there is a	another	< character, as	a pat-
       tern that uses <	as its delimiter.

       Before each data	line is	 passed	 to  pcre[16|32]_exec(),  leading  and
       trailing	 white space is	removed, and it	is then	scanned	for \ escapes.
       Some of these are pretty	esoteric features, intended for	 checking  out
       some  of	the more complicated features of PCRE. If you are just testing
       "ordinary" regular expressions, you probably don't need any  of	these.
       The following escapes are recognized:

	 \a	    alarm (BEL,	\x07)
	 \b	    backspace (\x08)
	 \e	    escape (\x27)
	 \f	    form feed (\x0c)
	 \n	    newline (\x0a)
	 \qdd	    set	the PCRE_MATCH_LIMIT limit to dd
		      (any number of digits)
	 \r	    carriage return (\x0d)
	 \t	    tab	(\x09)
	 \v	    vertical tab (\x0b)
	 \nnn	    octal character (up	to 3 octal digits); always
		      a	byte unless > 255 in UTF-8 or 16-bit or	32-bit mode
	 \o{dd...}  octal character (any number	of octal digits}
	 \xhh	    hexadecimal	byte (up to 2 hex digits)
	 \x{hh...}  hexadecimal	character (any number of hex digits)
	 \A	    pass the PCRE_ANCHORED option to pcre[16|32]_exec()
		      or pcre[16|32]_dfa_exec()
	 \B	    pass the PCRE_NOTBOL option	to pcre[16|32]_exec()
		      or pcre[16|32]_dfa_exec()
	 \Cdd	    call pcre[16|32]_copy_substring() for substring dd
		      after a successful match (number less than 32)
	 \Cname	    call pcre[16|32]_copy_named_substring() for	substring
		      "name" after a successful	match (name termin-
		      ated by next non alphanumeric character)
	 \C+	    show the current captured substrings at callout
	 \C-	    do not supply a callout function
	 \C!n	    return 1 instead of	0 when callout number n	is
	 \C!n!m	    return 1 instead of	0 when callout number n	is
		      reached for the nth time
	 \C*n	    pass the number n (may be negative)	as callout
		      data; this is used as the	callout	return value
	 \D	    use	the pcre[16|32]_dfa_exec() match function
	 \F	    only shortest match	for pcre[16|32]_dfa_exec()
	 \Gdd	    call pcre[16|32]_get_substring() for substring dd
		      after a successful match (number less than 32)
	 \Gname	    call pcre[16|32]_get_named_substring() for substring
		      "name" after a successful	match (name termin-
		      ated by next non-alphanumeric character)
	 \Jdd	    set	up a JIT stack of dd kilobytes maximum (any
		      number of	digits)
	 \L	    call pcre[16|32]_get_substringlist() after a
		      successful match
	 \M	    discover the minimum MATCH_LIMIT and
		      MATCH_LIMIT_RECURSION settings
	 \N	    pass the PCRE_NOTEMPTY option to pcre[16|32]_exec()
		      or pcre[16|32]_dfa_exec(); if used twice,	pass the
	 \Odd	    set	the size of the	output vector passed to
		      pcre[16|32]_exec() to dd (any number of digits)
	 \P	    pass the PCRE_PARTIAL_SOFT option to pcre[16|32]_exec()
		      or pcre[16|32]_dfa_exec(); if used twice,	pass the
		      PCRE_PARTIAL_HARD	option
	 \Qdd	    set	the PCRE_MATCH_LIMIT_RECURSION limit to	dd
		      (any number of digits)
	 \R	    pass the PCRE_DFA_RESTART option to	pcre[16|32]_dfa_exec()
	 \S	    output details of memory get/free calls during matching
	 \Y		pass	 the	PCRE_NO_START_OPTIMIZE	  option    to
		      or pcre[16|32]_dfa_exec()
	 \Z	    pass the PCRE_NOTEOL option	to pcre[16|32]_exec()
		      or pcre[16|32]_dfa_exec()
	 \?	    pass the PCRE_NO_UTF[8|16|32]_CHECK	option to
		      pcre[16|32]_exec() or pcre[16|32]_dfa_exec()
	 \>dd	    start the match at offset dd (optional "-";	then
		      any number of digits); this sets the startoffset
		      argument	      for	 pcre[16|32]_exec()	    or
	 \<cr>	    pass the PCRE_NEWLINE_CR option to pcre[16|32]_exec()
		      or pcre[16|32]_dfa_exec()
	 \<lf>	    pass the PCRE_NEWLINE_LF option to pcre[16|32]_exec()
		      or pcre[16|32]_dfa_exec()
	 \<crlf>    pass the PCRE_NEWLINE_CRLF option to pcre[16|32]_exec()
		      or pcre[16|32]_dfa_exec()
	 \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre[16|32]_exec()
		      or pcre[16|32]_dfa_exec()
	 \<any>	    pass the PCRE_NEWLINE_ANY option to	pcre[16|32]_exec()
		      or pcre[16|32]_dfa_exec()

       The  use	of \x{hh...} is	not dependent on the use of the	/8 modifier on
       the pattern. It is recognized always. There may be any number of	 hexa-
       decimal	digits	inside	the  braces; invalid values provoke error mes-

       Note that \xhh specifies	one byte rather	than one  character  in	 UTF-8
       mode;  this  makes it possible to construct invalid UTF-8 sequences for
       testing purposes. On the	other hand, \x{hh} is interpreted as  a	 UTF-8
       character  in UTF-8 mode, generating more than one byte if the value is
       greater than 127.  When testing the 8-bit library not  in  UTF-8	 mode,
       \x{hh} generates	one byte for values less than 256, and causes an error
       for greater values.

       In UTF-16 mode, all 4-digit \x{hhhh} values are accepted. This makes it
       possible	to construct invalid UTF-16 sequences for testing purposes.

       In  UTF-32  mode,  all  4- to 8-digit \x{...} values are	accepted. This
       makes it	possible to construct invalid  UTF-32  sequences  for  testing

       The escapes that	specify	line ending sequences are literal strings, ex-
       actly as	shown. No more than one	newline	setting	should be  present  in
       any data	line.

       A  backslash  followed by anything else just escapes the	anything else.
       If the very last	character is a backslash, it is	ignored. This gives  a
       way  of	passing	 an empty line as data,	since a	real empty line	termi-
       nates the data input.

       The \J escape provides a	way of setting the maximum stack size that  is
       used  by	the just-in-time optimization code. It is ignored if JIT opti-
       mization	is not being used. Providing a stack that is larger  than  the
       default 32K is necessary	only for very complicated patterns.

       If \M is	present, pcretest calls	pcre[16|32]_exec() several times, with
       different values	in the match_limit and match_limit_recursion fields of
       the  pcre[16|32]_extra  data structure, until it	finds the minimum num-
       bers for	each parameter that allow pcre[16|32]_exec() to	complete with-
       out error. Because this is testing a specific feature of	the normal in-
       terpretive pcre[16|32]_exec() execution,	the use	of any	JIT  optimiza-
       tion  that might	have been set up by the	/S+ qualifier of -s+ option is

       The match_limit number is a measure of the amount of backtracking  that
       takes  place,  and  checking it out can be instructive. For most	simple
       matches,	the number is quite small, but for patterns  with  very	 large
       numbers	of  matching  possibilities,  it can become large very quickly
       with increasing length of  subject  string.  The	 match_limit_recursion
       number  is  a  measure  of how much stack (or, if PCRE is compiled with
       NO_RECURSE, how much heap) memory is needed to complete the  match  at-

       When  \O	 is  used, the value specified may be higher or	lower than the
       size set	by the -O command line option (or defaulted to 45); \O applies
       only  to	 the  call  of pcre[16|32]_exec() for the line in which	it ap-

       If the /P modifier was present on the pattern, causing the POSIX	 wrap-
       per API to be used, the only option-setting sequences that have any ef-
       fect are	\B, \N,	and \Z,	causing	REG_NOTBOL, REG_NOTEMPTY, and  REG_NO-
       TEOL, respectively, to be passed	to regexec().

       By   default,  pcretest	uses  the  standard  PCRE  matching  function,
       pcre[16|32]_exec() to match each	data line. PCRE	also supports  an  al-
       ternative  matching function, pcre[16|32]_dfa_test(), which operates in
       a different way,	and has	some restrictions. The differences between the
       two functions are described in the pcrematching documentation.

       If  a data line contains	the \D escape sequence,	or if the command line
       contains	the -dfa option, the alternative matching  function  is	 used.
       This function finds all possible	matches	at a given point. If, however,
       the \F escape sequence is present in the	data line, it stops after  the
       first match is found. This is always the	shortest possible match.

       This  section  describes	 the output when the normal matching function,
       pcre[16|32]_exec(), is being used.

       When a match succeeds, pcretest outputs the list	of captured substrings
       that  pcre[16|32]_exec()	returns, starting with number 0	for the	string
       that matched the	whole pattern. Otherwise, it outputs "No  match"  when
       the  return is PCRE_ERROR_NOMATCH, and "Partial match:" followed	by the
       partially matching substring when pcre[16|32]_exec()  returns  PCRE_ER-
       ROR_PARTIAL. (Note that this is the entire substring that was inspected
       during the partial match; it may	include	characters before  the	actual
       match start if a	lookbehind assertion, \K, \b, or \B was	involved.) For
       any other return, pcretest outputs the PCRE negative error number and a
       short  descriptive  phrase.  If the error is a failed UTF string	check,
       the offset of the start of the failing character	and  the  reason  code
       are  also  output,  provided  that  the size of the output vector is at
       least two. Here is an example of	an interactive pcretest	run.

	 $ pcretest
	 PCRE version 8.13 2011-04-30

	   re> /^abc(\d+)/
	 data> abc123
	  0: abc123
	  1: 123
	 data> xyz
	 No match

       Unset capturing substrings that are not followed	by one that is set are
       not  returned  by pcre[16|32]_exec(), and are not shown by pcretest. In
       the following example, there are	two capturing substrings, but when the
       first  data  line is matched, the second, unset substring is not	shown.
       An "internal" unset substring is	shown as "<unset>", as for the	second
       data line.

	   re> /(a)|(b)/
	 data> a
	  0: a
	  1: a
	 data> b
	  0: b
	  1: <unset>
	  2: b

       If  the strings contain any non-printing	characters, they are output as
       \xhh escapes if the value is less than 256 and UTF  mode	 is  not  set.
       Otherwise they are output as \x{hh...} escapes. See below for the defi-
       nition of non-printing characters. If the pattern has the /+  modifier,
       the  output  for	substring 0 is followed	by the the rest	of the subject
       string, identified by "0+" like this:

	   re> /cat/+
	 data> cataract
	  0: cat
	  0+ aract

       If the pattern has the /g or /G modifier,  the  results	of  successive
       matching	attempts are output in sequence, like this:

	   re> /\Bi(\w\w)/g
	 data> Mississippi
	  0: iss
	  1: ss
	  0: iss
	  1: ss
	  0: ipp
	  1: pp

       "No  match" is output only if the first match attempt fails. Here is an
       example of a failure message (the offset	4 that is specified by \>4  is
       past the	end of the subject string):

	   re> /xyz/
	 data> xyz\>4
	 Error -24 (bad	offset value)

       If  any	of the sequences \C, \G, or \L are present in a	data line that
       is successfully matched,	the substrings extracted  by  the  convenience
       functions are output with C, G, or L after the string number instead of
       a colon.	This is	in addition to the normal full list. The string	length
       (that  is,  the return from the extraction function) is given in	paren-
       theses after each string	for \C and \G.

       Note that whereas patterns can be continued over	several	lines (a plain
       ">" prompt is used for continuations), data lines may not. However new-
       lines can be included in	data by	means of the \n	escape (or  \r,	 \r\n,
       etc., depending on the newline sequence setting).

       When the	alternative matching function, pcre[16|32]_dfa_exec(), is used
       (by means of the	\D escape sequence or the -dfa command	line  option),
       the  output  consists  of  a  list of all the matches that start	at the
       first point in the subject where	there is at least one match. For exam-

	   re> /(tang|tangerine|tan)/
	 data> yellow tangerine\D
	  0: tangerine
	  1: tang
	  2: tan

       (Using  the  normal  matching function on this data finds only "tang".)
       The longest matching string is always given first (and numbered	zero).
       After a PCRE_ERROR_PARTIAL return, the output is	"Partial match:", fol-
       lowed by	the partially matching substring. (Note	that this is  the  en-
       tire  substring that was	inspected during the partial match; it may in-
       clude characters	before the actual match	start if a  lookbehind	asser-
       tion, \K, \b, or	\B was involved.)

       If /g is	present	on the pattern,	the search for further matches resumes
       at the end of the longest match.	For example:

	   re> /(tang|tangerine|tan)/g
	 data> yellow tangerine	and tangy sultana\D
	  0: tangerine
	  1: tang
	  2: tan
	  0: tang
	  1: tan
	  0: tan

       Since the matching function does	not support substring capture, the es-
       cape sequences that are concerned with captured substrings are not rel-

       When the	alternative matching function has given	the PCRE_ERROR_PARTIAL
       return,	indicating that	the subject partially matched the pattern, you
       can restart the match with additional subject data by means of  the  \R
       escape sequence.	For example:

	   re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
	 data> 23ja\P\D
	 Partial match:	23ja
	 data> n05\R\D
	  0: n05

       For  further  information  about	 partial matching, see the pcrepartial

       If the pattern contains any callout requests, pcretest's	callout	 func-
       tion  is	 called	 during	 matching. This	works with both	matching func-
       tions. By default, the called function displays the callout number, the
       start  and  current  positions in the text at the callout time, and the
       next pattern item to be tested. For example:

	   0	^  ^	 \d

       This output indicates that callout number 0 occurred for	 a  match  at-
       tempt  starting at the fourth character of the subject string, when the
       pointer was at the seventh character of the data,  and  when  the  next
       pattern	item  was  \d.	Just one circumflex is output if the start and
       current positions are the same.

       Callouts	numbered 255 are assumed to be automatic callouts, inserted as
       a  result  of the /C pattern modifier. In this case, instead of showing
       the callout number, the offset in the pattern, preceded by a  plus,  is
       output. For example:

	   re> /\d?[A-E]\*/C
	 data> E*
	  +0 ^	    \d?
	  +3 ^	    [A-E]
	  +8 ^^	    \*
	 +10 ^ ^
	  0: E*

       If a pattern contains (*MARK) items, an additional line is output when-
       ever a change of	latest mark is passed to the callout function. For ex-

	   re> /a(*MARK:X)bc/C
	 data> abc
	  +0 ^	     a
	  +1 ^^	     (*MARK:X)
	 +10 ^^	     b
	 Latest	Mark: X
	 +11 ^ ^     c
	 +12 ^	^
	  0: abc

       The  mark  changes between matching "a" and "b",	but stays the same for
       the rest	of the match, so nothing more is output. If, as	 a  result  of
       backtracking,  the  mark	 reverts to being unset, the text "<unset>" is

       The callout function in pcretest	returns	zero (carry  on	 matching)  by
       default,	 but you can use a \C item in a	data line (as described	above)
       to change this and other	parameters of the callout.

       Inserting callouts can be helpful when using pcretest to	check  compli-
       cated  regular expressions. For further information about callouts, see
       the pcrecallout documentation.

       When pcretest is	outputting text	in the compiled	version	of a  pattern,
       bytes  other  than 32-126 are always treated as non-printing characters
       are are therefore shown as hex escapes.

       When pcretest is	outputting text	that is	a matched part	of  a  subject
       string,	it behaves in the same way, unless a different locale has been
       set for the pattern (using the /L modifier).  In	 this  case,  the  is-
       print() function	to distinguish printing	and non-printing characters.

       The  facilities	described  in  this section are	not available when the
       POSIX interface to PCRE is being	used, that is,	when  the  /P  pattern
       modifier	is specified.

       When the	POSIX interface	is not in use, you can cause pcretest to write
       a compiled pattern to a file, by	following the modifiers	with >	and  a
       file name.  For example:

	 /pattern/im >/some/file

       See  the	pcreprecompile documentation for a discussion about saving and
       re-using	compiled patterns.  Note that if the pattern was  successfully
       studied with JIT	optimization, the JIT data cannot be saved.

       The  data  that	is  written  is	 binary. The first eight bytes are the
       length of the compiled pattern data followed by the length of  the  op-
       tional study data, each written as four bytes in	big-endian order (most
       significant byte	first).	If there is no study data (either the  pattern
       was  not	 studied,  or  studying	 did  not return any data), the	second
       length is zero. The lengths are followed	by an exact copy of  the  com-
       piled  pattern.	If there is additional study data, this	(excluding any
       JIT data) follows immediately after the compiled	pattern. After writing
       the file, pcretest expects to read a new	pattern.

       A  saved	 pattern  can  be reloaded into	pcretest by specifying < and a
       file name instead of a pattern. There must be no	space  between	<  and
       the  file  name,	 which	must  not  contain a < character, as otherwise
       pcretest	will interpret the line	as a pattern delimited	by  <  charac-
       ters. For example:

	  re> </some/file
	 Compiled pattern loaded from /some/file
	 No study data

       If  the	pattern	 was previously	studied	with the JIT optimization, the
       JIT information cannot be saved and restored, and so is lost. When  the
       pattern	has  been  loaded, pcretest proceeds to	read data lines	in the
       usual way.

       You can copy a file written by pcretest to a different host and	reload
       it  there,  even	 if the	new host has opposite endianness to the	one on
       which the pattern was compiled. For example, you	can compile on an  i86
       machine	and  run  on  a	SPARC machine. When a pattern is reloaded on a
       host with different endianness, the confirmation	message	is changed to:

	 Compiled pattern (byte-inverted) loaded from /some/file

       The test	suite contains some saved pre-compiled patterns	with different
       endianness.  These  are	reloaded  using	"<!" instead of	just "<". This
       suppresses the "(byte-inverted)"	text so	that the output	is the same on
       all  hosts.  It	also forces debugging output once the pattern has been

       File names for saving and reloading can be absolute  or	relative,  but
       note  that the shell facility of	expanding a file name that starts with
       a tilde (~) is not available.

       The ability to save and reload files in pcretest	is intended for	 test-
       ing  and	experimentation. It is not intended for	production use because
       only a single pattern can be written to a file. Furthermore,  there  is
       no  facility  for  supplying  custom  character	tables	for use	with a
       reloaded	pattern. If the	original pattern was compiled with custom  ta-
       bles,  an attempt to match a subject string using a reloaded pattern is
       likely to cause pcretest	to crash.  Finally, if you attempt to  load  a
       file that is not	in the correct format, the result is undefined.

       pcre(3),	 pcre16(3),  pcre32(3),	 pcreapi(3),  pcrecallout(3), pcrejit,
       pcrematching(3),	pcrepartial(d),	pcrepattern(3),	pcreprecompile(3).

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

       Last updated: 09	February 2014
       Copyright (c) 1997-2014 University of Cambridge.

PCRE 8.35		       09 February 2014			   PCRETEST(1)


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