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PCRETEST(1)									      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.


       From  release  8.30,  two  separate PCRE libraries can be built. The original one supports
       8-bit character strings, whereas the  newer  16-bit  library  supports  character  strings
       encoded in 16-bit units. From release 8.32, a third library can be built, supporting char-
       acter strings encoded 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.
       Results 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 or pcre16_xx when using the 16-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 error.

       -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) modifier; the internal
		 form is output after compilation.

       -C	 Output the version number of the PCRE library,  and  all  available  information
		 about	the optional features that are included, and then exit. All other options
		 are ignored.

       -C option Output information about a specific build-time option, then exit. This function-
		 ality is intended for use in scripts such as RunTest. The following options out-
		 put the value indicated:

		   ebcdic-nl  the code for LF (= NL) in an EBCDIC environment:
				0x15 or 0x25
				0 if used in an ASCII environment
		   linksize   the internal link size (2, 3, or 4)
		   newline    the default newline setting:

		 The following options output 1 for true or zero for false:

		   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

       -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 equiv-
		 alent 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 expression. The size is given	in  bytes
		 for both libraries.

       -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
		 different 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 execution.

       -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 pat-
		 tern 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 follows:

		   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 are pattern options that can override -s, either  specifying  no
		 studying at all, or suppressing JIT compilation.

		 If the /I or /D option is present on a pattern (requesting output about the com-
		 piled pattern), information about the result 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  resources  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 specific patterns that should never be studied (see the /S pattern  modifier

       -t	 Run each compile, study, and match many times with a timer, and output resulting
		 time per compile 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 separate item on the command line). For example, "-t
		 1000" would iterate 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.


       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 out-
       put 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 number of data lines to be matched
       against the 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 expression may be continued
       over  several input lines, in which case the newline 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 followed 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 expression.


       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 modifiers. White
       space may appear between the final pattern delimiter and the first modifier,  and  between
       the  modifiers  themselves. For reference, 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
	 /?		 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
	 /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 mod-
       ifier 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 compile-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  mul-
       tiline 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 using 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 documentation.

   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 difference 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 entire  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 (including \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() function. 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 remainder of the subject string.  This  is
       useful  for tests where the subject 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 meanings.

       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 corresponding to higher numbers should be set  to  -1,  and  these  are  output  as
       "<unset>". This modifier gives a way of checking that this is happening.

       The  /B modifier is a debugging feature. It requests that pcretest output a representation
       of the compiled code after compilation. Normally this information contains length and off-
       set  values;  however,  if  /Z is also present, this data is replaced by spaces. This is a
       special feature 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 compiled on a host with a different endianness. This feature is
       not available 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

       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  compiling a pattern. If the pattern is studied, the results
       of that are also output.

       The /K modifier requests pcretest to show names from backtracking control 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  already   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 example,


       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. With-
       out an /L (or /T) modifier, NULL is passed as the tables pointer; that is, /L applies only
       to the expression 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 /S modifier causes pcre[16|32]_study() to be called after the expression has been com-
       piled, and the results used when the expression is matched. There are a number of qualify-
       ing 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  actu-
       ally 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 documentation. 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 specific set of built-in
       character tables to be passed to pcre[16|32]_compile(). 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  identified  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() function:

	 /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 ignored.


       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  follow-
       ing 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
	 \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 terminated
		      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 terminated
		      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 pcre[16|32]_exec()
		      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 pcre[16|32]_dfa_exec()
	 \<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	hexadecimal  digits  inside  the  braces;
       invalid values provoke error messages.

       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 con-
       struct 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 purposes.

       The  escapes  that specify line ending sequences are literal strings, exactly 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 terminates 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 optimization is not being used. Providing
       a stack that is larger than the default 32K is necessary only for  very	complicated  pat-

       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  struc-
       ture,  until it finds the minimum numbers for each parameter that allow pcre[16|32]_exec()
       to complete without error. Because this is testing a specific feature of the normal inter-
       pretive pcre[16|32]_exec() execution, the use of any JIT optimization that might have been
       set up by the /S+ qualifier of -s+ option is disabled.

       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)  mem-
       ory is needed to complete the match attempt.

       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 appears.

       If  the	/P modifier was present on the pattern, causing the POSIX wrapper API to be used,
       the only option-setting sequences that have  any  effect  are  \B,  \N,	and  \Z,  causing
       REG_NOTBOL, REG_NOTEMPTY, and REG_NOTEOL, 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    alternative    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 "Par-
       tial  match:" followed by the partially matching substring when pcre[16|32]_exec() returns
       PCRE_ERROR_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  out-
       put, 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

	   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 definition 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 fail-
       ure 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 parenthe-
       ses 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 newlines 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 example:

	   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:", followed by the partially matching substring. (Note that this
       is the entire substring that was inspected during the partial match; it may include  char-
       acters  before  the  actual  match  start  if  a  lookbehind  assertion, \K, \b, or \B was

       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 escape sequences that
       are concerned with captured substrings are not relevant.


       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 documentation.


       If the pattern contains any callout requests, pcretest's callout function is called during
       matching.  This	works  with both matching functions. By default, the called function dis-
       plays 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 attempt 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  whenever  a  change  of
       latest mark is passed to the callout function. For example:

	   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 output.

       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 complicated regular expres-
       sions. 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

       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 modi-
       fier). In this case, the isprint() function to distinguish printing and non-printing char-


       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 optional 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 compiled 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. The name of the file must not contain a < character, as otherwise  pcretest  will
       interpret the line as a pattern delimited by < characters.  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 can-
       not be saved and restored, and so is lost. When the pattern has been loaded, pcretest pro-
       ceeds 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 reloaded.

       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 testing and  experimenta-
       tion.  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 tables, 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 September 2012
       Copyright (c) 1997-2012 University of Cambridge.

PCRE 8.32				10 September 2012			      PCRETEST(1)
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