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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.

       The input is processed using using C's string functions,	 so  must  not
       contain	binary	zeroes,	even though in Unix-like environments, fgets()
       treats any bytes	other than newline as data characters.

       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 the	8-bit library has been built, this option causes it to
		 be used (this is the default).	If the 8-bit library  has  not
		 been built, this option causes	an error.

       -16	 If  the  16-bit library has been built, this option causes it
		 to be used. If	only the 16-bit	library	has been  built,  this
		 is  the  default.  If	the 16-bit library has not been	built,
		 this option causes an error.

       -32	 If the	32-bit library has been	built, this option  causes  it
		 to  be	 used. If only the 32-bit library has been built, this
		 is the	default. If the	32-bit library	has  not  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: 10	February 2020
       Copyright (c) 1997-2020 University of Cambridge.

PCRE 8.44		       10 February 2020			   PCRETEST(1)


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