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PCRETEST(1)							   PCRETEST(1)

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


       pcretest [options] [source] [destination]

       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 documentation.


       -b	 Behave as if each regex has the /B (show bytecode)  modifier;
		 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
		 included, and then exit.

       -d	 Behave  as  if  each  regex  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_dfa_exec(),   to	 be   used  instead  of  the  standard
		 pcre_exec() function (more detail is given below).

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

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

       -m	 Output  the  size  of each compiled pattern after it has been
		 compiled. This is equivalent to adding  /M  to  each  regular
		 expression.   For  compatibility  with  earlier  versions  of
		 pcretest, -s is a synonym for -m.

       -o osize  Set the number of elements in the output vector that is  used
		 when  calling pcre_exec() or pcre_dfa_exec() to be osize. The
		 default value is 45, which is enough for 14 capturing	subex
		 pressions   for  pcre_exec()  or  22  different  matches  for
		 pcre_dfa_exec(). The vector size can be changed for  individ
		 ual  matching	calls  by  including  \O in the data line (see

       -p	 Behave as if each regex has the /P modifier; the POSIX  wrap
		 per  API  is used to call PCRE. None of the other options has
		 any effect when -p is set.

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

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

       -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 iter
		 ate 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

       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 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  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.  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. Whitespace may appear between the  final  pattern  delimiter
       and the first modifier, and between the modifiers themselves.

       The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,
       PCRE_DOTALL, or PCRE_EXTENDED  options,	respectively,  when  pcre_com
       pile()  is  called. These four modifier letters have the same effect as
       they do in Perl. For example:


       The following table shows additional modifiers for setting PCRE options
       that do not correspond to anything in Perl:


       Those  specifying  line	ending sequences are literal strings as shown,
       but the letters can be in either  case.	This  example  sets  multiline
       matching with CRLF as the line ending sequence:


       Details	of the meanings of these PCRE options are given in the pcreapi

   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_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_exec() in a /g or  /G  sequence  matches  an  empty
       string,	the next call is done with the PCRE_NOTEMPTY 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 by
       one, and the normal match is retried. This imitates the way  Perl  han
       dles such cases when using the /g modifier or the split() function.

   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.

       The  /B modifier is a debugging feature. It requests that pcretest out
       put a representation of the compiled byte code after compilation.  Nor
       mally  this  information contains length and offset 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 /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_maketables() is called to build a set of character tables for  the
       locale,	and  this  is then passed to pcre_compile() when compiling the
       regular expression. Without an /L  modifier,  NULL  is  passed  as  the
       tables  pointer; that is, /L applies only to the expression on which it

       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_fullinfo() after  compiling  a
       pattern.  If  the pattern is studied, the results of that are also out

       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 fields in
       the compiled pattern that  contain  2-byte  and	4-byte	numbers.  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 below.

       The  /S	modifier causes pcre_study() to be called after the expression
       has been compiled, and the results used when the expression is matched.

       The  /M	modifier causes the size of memory block used to hold the com
       piled pattern to be output.

       The /P modifier causes pcretest to call PCRE via the POSIX wrapper  API
       rather  than  its  native  API.	When this is done, all other modifiers
       except /i, /m, and /+ are ignored. REG_ICASE is set if /i  is  present,
       and  REG_NEWLINE  is  set if /m is present. The wrapper functions force
       PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is  set.

       The  /8 modifier causes pcretest to call PCRE with the PCRE_UTF8 option
       set. This turns on support for UTF-8 character handling in  PCRE,  pro
       vided  that  it	was  compiled with this support enabled. This modifier
       also causes any non-printing characters in output strings to be printed
       using the \x{hh...} notation if they are valid UTF-8 sequences.

       If  the	/?  modifier  is  used	with  /8,  it  causes pcretest to call
       pcre_compile() with the	PCRE_NO_UTF8_CHECK  option,  to  suppress  the
       checking of the string for UTF-8 validity.


       Before  each  data  line is passed to pcre_exec(), leading and trailing
       whitespace 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	"ordi
       nary"  regular  expressions,  you probably dont need any of these. The
       following escapes are recognized:

	 \a	    alarm (BEL, \x07)
	 \b	    backspace (\x08)
	 \e	    escape (\x27)
	 \f	    formfeed (\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)
	 \xhh	    hexadecimal character (up to 2 hex digits)
	 \x{hh...}  hexadecimal character, any number of digits
		      in UTF-8 mode
	 \A	    pass the PCRE_ANCHORED option to pcre_exec()
		      or pcre_dfa_exec()
	 \B	    pass the PCRE_NOTBOL option to pcre_exec()
		      or pcre_dfa_exec()
	 \Cdd	    call pcre_copy_substring() for substring dd
		      after a successful match (number less than 32)
	 \Cname     call pcre_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_dfa_exec() match function
	 \F	    only shortest match for pcre_dfa_exec()
	 \Gdd	    call pcre_get_substring() for substring dd
		      after a successful match (number less than 32)
	 \Gname     call pcre_get_named_substring() for substring
		      "name" after a successful match (name termin-
		      ated by next non-alphanumeric character)
	 \L	    call pcre_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_exec()
		      or pcre_dfa_exec()
	 \Odd	    set the size of the output vector passed to
		      pcre_exec() to dd (any number of digits)
	 \P	    pass the PCRE_PARTIAL option to pcre_exec()
		      or pcre_dfa_exec()
	 \Qdd	    set the PCRE_MATCH_LIMIT_RECURSION limit to dd
		      (any number of digits)
	 \R	    pass the PCRE_DFA_RESTART option to pcre_dfa_exec()
	 \S	    output details of memory get/free calls during matching
	 \Z	    pass the PCRE_NOTEOL option to pcre_exec()
		      or pcre_dfa_exec()
	 \?	    pass the PCRE_NO_UTF8_CHECK option to
		      pcre_exec() or pcre_dfa_exec()
	 \>dd	    start the match at offset dd (any number of digits);
		      this sets the startoffset argument for pcre_exec()
		      or pcre_dfa_exec()
	 \	    pass the PCRE_NEWLINE_CR option to pcre_exec()
		      or pcre_dfa_exec()
	 \	    pass the PCRE_NEWLINE_LF option to pcre_exec()
		      or pcre_dfa_exec()
	 \    pass the PCRE_NEWLINE_CRLF option to pcre_exec()
		      or pcre_dfa_exec()
	 \ pass the PCRE_NEWLINE_ANYCRLF option to pcre_exec()
		      or pcre_dfa_exec()
	 \     pass the PCRE_NEWLINE_ANY option to pcre_exec()
		      or pcre_dfa_exec()

       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	termi
       nates the data input.

       If  \M  is present, pcretest calls pcre_exec() several times, with dif
       ferent values in the match_limit and  match_limit_recursion  fields  of
       the  pcre_extra	data structure, until it finds the minimum numbers for
       each parameter that allow pcre_exec() to complete. The match_limit num
       ber  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 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_exec() for the line in which it appears.

       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
       effect  are \B and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively,
       to be passed to regexec().

       The use of \x{hh...} to represent UTF-8 characters 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.  The
       result  is  from  one  to  six bytes, encoded according to the original
       UTF-8 rules of RFC 2279. This allows for  values  in  the  range  0  to
       0x7FFFFFFF.  Note  that not all of those are valid Unicode code points,
       or indeed valid UTF-8 characters according to the later	rules  in  RFC


       By   default,  pcretest	uses  the  standard  PCRE  matching  function,
       pcre_exec() to match each data line. From release 6.0, PCRE supports an
       alternative  matching  function,  pcre_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  called.
       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_exec(), is being used.

       When a match succeeds, pcretest outputs the list of captured substrings
       that  pcre_exec()  returns,  starting with number 0 for the string that
       matched the whole pattern. Otherwise, it outputs "No match" or "Partial
       match"  when  pcre_exec() returns PCRE_ERROR_NOMATCH or PCRE_ERROR_PAR
       TIAL, respectively, and otherwise the PCRE negative error number.  Here
       is an example of an interactive pcretest run.

	 $ pcretest
	 PCRE version 7.0 30-Nov-2006

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

       If  the strings contain any non-printing characters, they are output as
       \0x escapes, or as \x{...} escapes if the /8 modifier  was  present  on
       the  pattern.  See below for the definition of non-printing characters.
       If the pattern has the /+ modifier, the output for substring 0 is  fol
       lowed  by  the  the rest of the subject string, identified by "0+" like

	   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.

       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_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).

       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


       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, pcretests 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, the output

	   0	^  ^	 \d

       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*

       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.

       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
       isprint() function to distinguish printing and non-printing characters.


       The facilities described in this section are  not  available  when  the
       POSIX inteface to PCRE is being used, that is, when the /P pattern mod
       ifier 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.

       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 sec
       ond length is zero. The lengths are followed by an exact  copy  of  the
       compiled pattern. If there is additional study data, this follows imme
       diately after the compiled pattern. After writing  the  file,  pcretest
       expects to read a new pattern.

       A saved pattern can be reloaded into pcretest by specifing < 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:


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