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1 PCRETEST(1) General Commands Manual PCRETEST(1)
6 pcretest - a program for testing Perl-compatible regular expressions.
10 pcretest [options] [input file [output file]]
12 pcretest was written as a test program for the PCRE regular expression
13 library itself, but it can also be used for experimenting with regular
14 expressions. This document describes the features of the test program;
15 for details of the regular expressions themselves, see the pcrepattern
16 documentation. For details of the PCRE library function calls and their
17 options, see the pcreapi , pcre16 and pcre32 documentation.
19 The input for pcretest is a sequence of regular expression patterns and
20 strings to be matched, as described below. The output shows the result
21 of each match. Options on the command line and the patterns control
22 PCRE options and exactly what is output.
24 As PCRE has evolved, it has acquired many different features, and as a
25 result, pcretest now has rather a lot of obscure options for testing
26 every possible feature. Some of these options are specifically designed
27 for use in conjunction with the test script and data files that are
28 distributed as part of PCRE, and are unlikely to be of use otherwise.
29 They are all documented here, but without much justification.
34 Input to pcretest is processed line by line, either by calling the C
35 library's fgets() function, or via the libreadline library (see below).
36 In Unix-like environments, fgets() treats any bytes other than newline
37 as data characters. However, in some Windows environments character 26
38 (hex 1A) causes an immediate end of file, and no further data is read.
39 For maximum portability, therefore, it is safest to use only ASCII
40 characters in pcretest input files.
45 From release 8.30, two separate PCRE libraries can be built. The origi-
46 nal one supports 8-bit character strings, whereas the newer 16-bit
47 library supports character strings encoded in 16-bit units. From
48 release 8.32, a third library can be built, supporting character
49 strings encoded in 32-bit units. The pcretest program can be used to
50 test all three libraries. However, it is itself still an 8-bit program,
51 reading 8-bit input and writing 8-bit output. When testing the 16-bit
52 or 32-bit library, the patterns and data strings are converted to 16-
53 or 32-bit format before being passed to the PCRE library functions.
54 Results are converted to 8-bit for output.
56 References to functions and structures of the form pcre[16|32]_xx below
57 mean "pcre_xx when using the 8-bit library, pcre16_xx when using the
58 16-bit library, or pcre32_xx when using the 32-bit library".
63 -8 If both the 8-bit library has been built, this option causes
64 the 8-bit library to be used (which is the default); if the
65 8-bit library has not been built, this option causes an
66 error.
68 -16 If both the 8-bit or the 32-bit, and the 16-bit libraries
69 have been built, this option causes the 16-bit library to be
70 used. If only the 16-bit library has been built, this is the
71 default (so has no effect). If only the 8-bit or the 32-bit
72 library has been built, this option causes an error.
74 -32 If both the 8-bit or the 16-bit, and the 32-bit libraries
75 have been built, this option causes the 32-bit library to be
76 used. If only the 32-bit library has been built, this is the
77 default (so has no effect). If only the 8-bit or the 16-bit
78 library has been built, this option causes an error.
80 -b Behave as if each pattern has the /B (show byte code) modi-
81 fier; the internal form is output after compilation.
83 -C Output the version number of the PCRE library, and all avail-
84 able information about the optional features that are
85 included, and then exit with zero exit code. All other
86 options are ignored.
88 -C option Output information about a specific build-time option, then
89 exit. This functionality is intended for use in scripts such
90 as RunTest. The following options output the value and set
91 the exit code as indicated:
93 ebcdic-nl the code for LF (= NL) in an EBCDIC environment:
94 0x15 or 0x25
95 0 if used in an ASCII environment
96 exit code is always 0
97 linksize the configured internal link size (2, 3, or 4)
98 exit code is set to the link size
99 newline the default newline setting:
101 exit code is always 0
102 bsr the default setting for what \R matches:
104 exit code is always 0
106 The following options output 1 for true or 0 for false, and
107 set the exit code to the same value:
109 ebcdic compiled for an EBCDIC environment
110 jit just-in-time support is available
111 pcre16 the 16-bit library was built
112 pcre32 the 32-bit library was built
113 pcre8 the 8-bit library was built
114 ucp Unicode property support is available
115 utf UTF-8 and/or UTF-16 and/or UTF-32 support
116 is available
118 If an unknown option is given, an error message is output;
119 the exit code is 0.
121 -d Behave as if each pattern has the /D (debug) modifier; the
122 internal form and information about the compiled pattern is
123 output after compilation; -d is equivalent to -b -i.
125 -dfa Behave as if each data line contains the \D escape sequence;
126 this causes the alternative matching function,
127 pcre[16|32]_dfa_exec(), to be used instead of the standard
128 pcre[16|32]_exec() function (more detail is given below).
130 -help Output a brief summary these options and then exit.
132 -i Behave as if each pattern has the /I modifier; information
133 about the compiled pattern is given after compilation.
135 -M Behave as if each data line contains the \M escape sequence;
136 this causes PCRE to discover the minimum MATCH_LIMIT and
137 MATCH_LIMIT_RECURSION settings by calling pcre[16|32]_exec()
138 repeatedly with different limits.
140 -m Output the size of each compiled pattern after it has been
141 compiled. This is equivalent to adding /M to each regular
142 expression. The size is given in bytes for both libraries.
144 -O Behave as if each pattern has the /O modifier, that is dis-
145 able auto-possessification for all patterns.
147 -o osize Set the number of elements in the output vector that is used
148 when calling pcre[16|32]_exec() or pcre[16|32]_dfa_exec() to
149 be osize. The default value is 45, which is enough for 14
150 capturing subexpressions for pcre[16|32]_exec() or 22 differ-
151 ent matches for pcre[16|32]_dfa_exec(). The vector size can
152 be changed for individual matching calls by including \O in
153 the data line (see below).
155 -p Behave as if each pattern has the /P modifier; the POSIX
156 wrapper API is used to call PCRE. None of the other options
157 has any effect when -p is set. This option can be used only
158 with the 8-bit library.
160 -q Do not output the version number of pcretest at the start of
161 execution.
163 -S size On Unix-like systems, set the size of the run-time stack to
164 size megabytes.
166 -s or -s+ Behave as if each pattern has the /S modifier; in other
167 words, force each pattern to be studied. If -s+ is used, all
168 the JIT compile options are passed to pcre[16|32]_study(),
169 causing just-in-time optimization to be set up if it is
170 available, for both full and partial matching. Specific JIT
171 compile options can be selected by following -s+ with a digit
172 in the range 1 to 7, which selects the JIT compile modes as
173 follows:
175 1 normal match only
176 2 soft partial match only
177 3 normal match and soft partial match
178 4 hard partial match only
179 6 soft and hard partial match
180 7 all three modes (default)
182 If -s++ is used instead of -s+ (with or without a following
183 digit), the text "(JIT)" is added to the first output line
184 after a match or no match when JIT-compiled code was actually
185 used.
187 Note that there are pattern options that can override -s,
188 either specifying no studying at all, or suppressing JIT com-
189 pilation.
191 If the /I or /D option is present on a pattern (requesting
192 output about the compiled pattern), information about the
193 result of studying is not included when studying is caused
194 only by -s and neither -i nor -d is present on the command
195 line. This behaviour means that the output from tests that
196 are run with and without -s should be identical, except when
197 options that output information about the actual running of a
198 match are set.
200 The -M, -t, and -tm options, which give information about
201 resources used, are likely to produce different output with
202 and without -s. Output may also differ if the /C option is
203 present on an individual pattern. This uses callouts to trace
204 the the matching process, and this may be different between
205 studied and non-studied patterns. If the pattern contains
206 (*MARK) items there may also be differences, for the same
207 reason. The -s command line option can be overridden for spe-
208 cific patterns that should never be studied (see the /S pat-
209 tern modifier below).
211 -t Run each compile, study, and match many times with a timer,
212 and output the resulting times per compile, study, or match
213 (in milliseconds). Do not set -m with -t, because you will
214 then get the size output a zillion times, and the timing will
215 be distorted. You can control the number of iterations that
216 are used for timing by following -t with a number (as a sepa-
217 rate item on the command line). For example, "-t 1000" iter-
218 ates 1000 times. The default is to iterate 500000 times.
220 -tm This is like -t except that it times only the matching phase,
221 not the compile or study phases.
223 -T -TM These behave like -t and -tm, but in addition, at the end of
224 a run, the total times for all compiles, studies, and matches
225 are output.
230 If pcretest is given two filename arguments, it reads from the first
231 and writes to the second. If it is given only one filename argument, it
232 reads from that file and writes to stdout. Otherwise, it reads from
233 stdin and writes to stdout, and prompts for each line of input, using
234 "re>" to prompt for regular expressions, and "data>" to prompt for data
235 lines.
237 When pcretest is built, a configuration option can specify that it
238 should be linked with the libreadline library. When this is done, if
239 the input is from a terminal, it is read using the readline() function.
240 This provides line-editing and history facilities. The output from the
241 -help option states whether or not readline() will be used.
243 The program handles any number of sets of input on a single input file.
244 Each set starts with a regular expression, and continues with any num-
245 ber of data lines to be matched against that pattern.
247 Each data line is matched separately and independently. If you want to
248 do multi-line matches, you have to use the \n escape sequence (or \r or
249 \r\n, etc., depending on the newline setting) in a single line of input
250 to encode the newline sequences. There is no limit on the length of
251 data lines; the input buffer is automatically extended if it is too
252 small.
254 An empty line signals the end of the data lines, at which point a new
255 regular expression is read. The regular expressions are given enclosed
256 in any non-alphanumeric delimiters other than backslash, for example:
258 /(a|bc)x+yz/
260 White space before the initial delimiter is ignored. A regular expres-
261 sion may be continued over several input lines, in which case the new-
262 line characters are included within it. It is possible to include the
263 delimiter within the pattern by escaping it, for example
265 /abc\/def/
267 If you do so, the escape and the delimiter form part of the pattern,
268 but since delimiters are always non-alphanumeric, this does not affect
269 its interpretation. If the terminating delimiter is immediately fol-
270 lowed by a backslash, for example,
272 /abc/\
274 then a backslash is added to the end of the pattern. This is done to
275 provide a way of testing the error condition that arises if a pattern
276 finishes with a backslash, because
278 /abc\/
280 is interpreted as the first line of a pattern that starts with "abc/",
281 causing pcretest to read the next line as a continuation of the regular
282 expression.
287 A pattern may be followed by any number of modifiers, which are mostly
288 single characters, though some of these can be qualified by further
289 characters. Following Perl usage, these are referred to below as, for
290 example, "the /i modifier", even though the delimiter of the pattern
291 need not always be a slash, and no slash is used when writing modi-
292 fiers. White space may appear between the final pattern delimiter and
293 the first modifier, and between the modifiers themselves. For refer-
294 ence, here is a complete list of modifiers. They fall into several
295 groups that are described in detail in the following sections.
297 /8 set UTF mode
298 /9 set PCRE_NEVER_UTF (locks out UTF mode)
299 /? disable UTF validity check
300 /+ show remainder of subject after match
301 /= show all captures (not just those that are set)
304 /B show compiled code
306 /D same as /B plus /I
308 /F flip byte order in compiled pattern
310 /G find all matches (shorten string)
311 /g find all matches (use startoffset)
312 /I show information about pattern
313 /i set PCRE_CASELESS
315 /K show backtracking control names
316 /L set locale
317 /M show compiled memory size
321 /P use the POSIX wrapper
322 /Q test external stack check function
323 /S study the pattern after compilation
324 /s set PCRE_DOTALL
325 /T select character tables
327 /W set PCRE_UCP
328 /X set PCRE_EXTRA
329 /x set PCRE_EXTENDED
331 /Z don't show lengths in /B output
333 /<any> set PCRE_NEWLINE_ANY
334 /<anycrlf> set PCRE_NEWLINE_ANYCRLF
335 /<cr> set PCRE_NEWLINE_CR
336 /<crlf> set PCRE_NEWLINE_CRLF
337 /<lf> set PCRE_NEWLINE_LF
338 /<bsr_anycrlf> set PCRE_BSR_ANYCRLF
339 /<bsr_unicode> set PCRE_BSR_UNICODE
343 Perl-compatible modifiers
345 The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,
346 PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when
347 pcre[16|32]_compile() is called. These four modifier letters have the
348 same effect as they do in Perl. For example:
350 /caseless/i
353 Modifiers for other PCRE options
355 The following table shows additional modifiers for setting PCRE com-
356 pile-time options that do not correspond to anything in Perl:
358 /8 PCRE_UTF8 ) when using the 8-bit
359 /? PCRE_NO_UTF8_CHECK ) library
361 /8 PCRE_UTF16 ) when using the 16-bit
362 /? PCRE_NO_UTF16_CHECK ) library
364 /8 PCRE_UTF32 ) when using the 32-bit
365 /? PCRE_NO_UTF32_CHECK ) library
384 /<bsr_anycrlf> PCRE_BSR_ANYCRLF
385 /<bsr_unicode> PCRE_BSR_UNICODE
388 The modifiers that are enclosed in angle brackets are literal strings
389 as shown, including the angle brackets, but the letters within can be
390 in either case. This example sets multiline matching with CRLF as the
391 line ending sequence:
393 /^abc/m<CRLF>
395 As well as turning on the PCRE_UTF8/16/32 option, the /8 modifier
396 causes all non-printing characters in output strings to be printed
397 using the \x{hh...} notation. Otherwise, those less than 0x100 are out-
398 put in hex without the curly brackets.
400 Full details of the PCRE options are given in the pcreapi documenta-
401 tion.
403 Finding all matches in a string
405 Searching for all possible matches within each subject string can be
406 requested by the /g or /G modifier. After finding a match, PCRE is
407 called again to search the remainder of the subject string. The differ-
408 ence between /g and /G is that the former uses the startoffset argument
409 to pcre[16|32]_exec() to start searching at a new point within the
410 entire string (which is in effect what Perl does), whereas the latter
411 passes over a shortened substring. This makes a difference to the
412 matching process if the pattern begins with a lookbehind assertion
413 (including \b or \B).
415 If any call to pcre[16|32]_exec() in a /g or /G sequence matches an
416 empty string, the next call is done with the PCRE_NOTEMPTY_ATSTART and
417 PCRE_ANCHORED flags set in order to search for another, non-empty,
418 match at the same point. If this second match fails, the start offset
419 is advanced, and the normal match is retried. This imitates the way
420 Perl handles such cases when using the /g modifier or the split() func-
421 tion. Normally, the start offset is advanced by one character, but if
422 the newline convention recognizes CRLF as a newline, and the current
423 character is CR followed by LF, an advance of two is used.
425 Other modifiers
427 There are yet more modifiers for controlling the way pcretest operates.
429 The /+ modifier requests that as well as outputting the substring that
430 matched the entire pattern, pcretest should in addition output the
431 remainder of the subject string. This is useful for tests where the
432 subject contains multiple copies of the same substring. If the + modi-
433 fier appears twice, the same action is taken for captured substrings.
434 In each case the remainder is output on the following line with a plus
435 character following the capture number. Note that this modifier must
436 not immediately follow the /S modifier because /S+ and /S++ have other
437 meanings.
439 The /= modifier requests that the values of all potential captured
440 parentheses be output after a match. By default, only those up to the
441 highest one actually used in the match are output (corresponding to the
442 return code from pcre[16|32]_exec()). Values in the offsets vector cor-
443 responding to higher numbers should be set to -1, and these are output
444 as "<unset>". This modifier gives a way of checking that this is hap-
445 pening.
447 The /B modifier is a debugging feature. It requests that pcretest out-
448 put a representation of the compiled code after compilation. Normally
449 this information contains length and offset values; however, if /Z is
450 also present, this data is replaced by spaces. This is a special fea-
451 ture for use in the automatic test scripts; it ensures that the same
452 output is generated for different internal link sizes.
454 The /D modifier is a PCRE debugging feature, and is equivalent to /BI,
455 that is, both the /B and the /I modifiers.
457 The /F modifier causes pcretest to flip the byte order of the 2-byte
458 and 4-byte fields in the compiled pattern. This facility is for testing
459 the feature in PCRE that allows it to execute patterns that were com-
460 piled on a host with a different endianness. This feature is not avail-
461 able when the POSIX interface to PCRE is being used, that is, when the
462 /P pattern modifier is specified. See also the section about saving and
463 reloading compiled patterns below.
465 The /I modifier requests that pcretest output information about the
466 compiled pattern (whether it is anchored, has a fixed first character,
467 and so on). It does this by calling pcre[16|32]_fullinfo() after com-
468 piling a pattern. If the pattern is studied, the results of that are
469 also output. In this output, the word "char" means a non-UTF character,
470 that is, the value of a single data item (8-bit, 16-bit, or 32-bit,
471 depending on the library that is being tested).
473 The /K modifier requests pcretest to show names from backtracking con-
474 trol verbs that are returned from calls to pcre[16|32]_exec(). It
475 causes pcretest to create a pcre[16|32]_extra block if one has not
476 already been created by a call to pcre[16|32]_study(), and to set the
477 PCRE_EXTRA_MARK flag and the mark field within it, every time that
478 pcre[16|32]_exec() is called. If the variable that the mark field
479 points to is non-NULL for a match, non-match, or partial match,
480 pcretest prints the string to which it points. For a match, this is
481 shown on a line by itself, tagged with "MK:". For a non-match it is
482 added to the message.
484 The /L modifier must be followed directly by the name of a locale, for
485 example,
487 /pattern/Lfr_FR
489 For this reason, it must be the last modifier. The given locale is set,
490 pcre[16|32]_maketables() is called to build a set of character tables
491 for the locale, and this is then passed to pcre[16|32]_compile() when
492 compiling the regular expression. Without an /L (or /T) modifier, NULL
493 is passed as the tables pointer; that is, /L applies only to the
494 expression on which it appears.
496 The /M modifier causes the size in bytes of the memory block used to
497 hold the compiled pattern to be output. This does not include the size
498 of the pcre[16|32] block; it is just the actual compiled data. If the
499 pattern is successfully studied with the PCRE_STUDY_JIT_COMPILE option,
500 the size of the JIT compiled code is also output.
502 The /Q modifier is used to test the use of pcre_stack_guard. It must be
503 followed by '0' or '1', specifying the return code to be given from an
504 external function that is passed to PCRE and used for stack checking
505 during compilation (see the pcreapi documentation for details).
507 The /S modifier causes pcre[16|32]_study() to be called after the
508 expression has been compiled, and the results used when the expression
509 is matched. There are a number of qualifying characters that may follow
510 /S. They may appear in any order.
512 If /S is followed by an exclamation mark, pcre[16|32]_study() is called
513 with the PCRE_STUDY_EXTRA_NEEDED option, causing it always to return a
514 pcre_extra block, even when studying discovers no useful information.
516 If /S is followed by a second S character, it suppresses studying, even
517 if it was requested externally by the -s command line option. This
518 makes it possible to specify that certain patterns are always studied,
519 and others are never studied, independently of -s. This feature is used
520 in the test files in a few cases where the output is different when the
521 pattern is studied.
523 If the /S modifier is followed by a + character, the call to
524 pcre[16|32]_study() is made with all the JIT study options, requesting
525 just-in-time optimization support if it is available, for both normal
526 and partial matching. If you want to restrict the JIT compiling modes,
527 you can follow /S+ with a digit in the range 1 to 7:
529 1 normal match only
530 2 soft partial match only
531 3 normal match and soft partial match
532 4 hard partial match only
533 6 soft and hard partial match
534 7 all three modes (default)
536 If /S++ is used instead of /S+ (with or without a following digit), the
537 text "(JIT)" is added to the first output line after a match or no
538 match when JIT-compiled code was actually used.
540 Note that there is also an independent /+ modifier; it must not be
541 given immediately after /S or /S+ because this will be misinterpreted.
543 If JIT studying is successful, the compiled JIT code will automatically
544 be used when pcre[16|32]_exec() is run, except when incompatible run-
545 time options are specified. For more details, see the pcrejit documen-
546 tation. See also the \J escape sequence below for a way of setting the
547 size of the JIT stack.
549 Finally, if /S is followed by a minus character, JIT compilation is
550 suppressed, even if it was requested externally by the -s command line
551 option. This makes it possible to specify that JIT is never to be used
552 for certain patterns.
554 The /T modifier must be followed by a single digit. It causes a spe-
555 cific set of built-in character tables to be passed to pcre[16|32]_com-
556 pile(). It is used in the standard PCRE tests to check behaviour with
557 different character tables. The digit specifies the tables as follows:
559 0 the default ASCII tables, as distributed in
560 pcre_chartables.c.dist
561 1 a set of tables defining ISO 8859 characters
563 In table 1, some characters whose codes are greater than 128 are iden-
564 tified as letters, digits, spaces, etc.
566 Using the POSIX wrapper API
568 The /P modifier causes pcretest to call PCRE via the POSIX wrapper API
569 rather than its native API. This supports only the 8-bit library. When
570 /P is set, the following modifiers set options for the regcomp() func-
571 tion:
573 /i REG_ICASE
576 /s REG_DOTALL )
577 /U REG_UNGREEDY ) These options are not part of
578 /W REG_UCP ) the POSIX standard
579 /8 REG_UTF8 )
581 The /+ modifier works as described above. All other modifiers are
582 ignored.
584 Locking out certain modifiers
586 PCRE can be compiled with or without support for certain features such
587 as UTF-8/16/32 or Unicode properties. Accordingly, the standard tests
588 are split up into a number of different files that are selected for
589 running depending on which features are available. When updating the
590 tests, it is all too easy to put a new test into the wrong file by mis-
591 take; for example, to put a test that requires UTF support into a file
592 that is used when it is not available. To help detect such mistakes as
593 early as possible, there is a facility for locking out specific modi-
594 fiers. If an input line for pcretest starts with the string "< forbid "
595 the following sequence of characters is taken as a list of forbidden
596 modifiers. For example, in the test files that must not use UTF or Uni-
597 code property support, this line appears:
599 < forbid 8W
601 This locks out the /8 and /W modifiers. An immediate error is given if
602 they are subsequently encountered. If the character string contains <
603 but not >, all the multi-character modifiers that begin with < are
604 locked out. Otherwise, such modifiers must be explicitly listed, for
605 example:
607 < forbid <JS><cr>
609 There must be a single space between < and "forbid" for this feature to
610 be recognised. If there is not, the line is interpreted either as a
611 request to re-load a pre-compiled pattern (see "SAVING AND RELOADING
612 COMPILED PATTERNS" below) or, if there is a another < character, as a
613 pattern that uses < as its delimiter.
618 Before each data line is passed to pcre[16|32]_exec(), leading and
619 trailing white space is removed, and it is then scanned for \ escapes.
620 Some of these are pretty esoteric features, intended for checking out
621 some of the more complicated features of PCRE. If you are just testing
622 "ordinary" regular expressions, you probably don't need any of these.
623 The following escapes are recognized:
625 \a alarm (BEL, \x07)
626 \b backspace (\x08)
627 \e escape (\x27)
628 \f form feed (\x0c)
629 \n newline (\x0a)
630 \qdd set the PCRE_MATCH_LIMIT limit to dd
631 (any number of digits)
632 \r carriage return (\x0d)
633 \t tab (\x09)
634 \v vertical tab (\x0b)
635 \nnn octal character (up to 3 octal digits); always
636 a byte unless > 255 in UTF-8 or 16-bit or 32-bit mode
637 \o{dd...} octal character (any number of octal digits}
638 \xhh hexadecimal byte (up to 2 hex digits)
639 \x{hh...} hexadecimal character (any number of hex digits)
640 \A pass the PCRE_ANCHORED option to pcre[16|32]_exec()
641 or pcre[16|32]_dfa_exec()
642 \B pass the PCRE_NOTBOL option to pcre[16|32]_exec()
643 or pcre[16|32]_dfa_exec()
644 \Cdd call pcre[16|32]_copy_substring() for substring dd
645 after a successful match (number less than 32)
646 \Cname call pcre[16|32]_copy_named_substring() for substring
647 "name" after a successful match (name termin-
648 ated by next non alphanumeric character)
649 \C+ show the current captured substrings at callout
650 time
651 \C- do not supply a callout function
652 \C!n return 1 instead of 0 when callout number n is
653 reached
654 \C!n!m return 1 instead of 0 when callout number n is
655 reached for the nth time
656 \C*n pass the number n (may be negative) as callout
657 data; this is used as the callout return value
658 \D use the pcre[16|32]_dfa_exec() match function
659 \F only shortest match for pcre[16|32]_dfa_exec()
660 \Gdd call pcre[16|32]_get_substring() for substring dd
661 after a successful match (number less than 32)
662 \Gname call pcre[16|32]_get_named_substring() for substring
663 "name" after a successful match (name termin-
664 ated by next non-alphanumeric character)
665 \Jdd set up a JIT stack of dd kilobytes maximum (any
666 number of digits)
667 \L call pcre[16|32]_get_substringlist() after a
668 successful match
669 \M discover the minimum MATCH_LIMIT and
671 \N pass the PCRE_NOTEMPTY option to pcre[16|32]_exec()
672 or pcre[16|32]_dfa_exec(); if used twice, pass the
674 \Odd set the size of the output vector passed to
675 pcre[16|32]_exec() to dd (any number of digits)
676 \P pass the PCRE_PARTIAL_SOFT option to pcre[16|32]_exec()
677 or pcre[16|32]_dfa_exec(); if used twice, pass the
679 \Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd
680 (any number of digits)
681 \R pass the PCRE_DFA_RESTART option to pcre[16|32]_dfa_exec()
682 \S output details of memory get/free calls during matching
683 \Y pass the PCRE_NO_START_OPTIMIZE option to
684 pcre[16|32]_exec()
685 or pcre[16|32]_dfa_exec()
686 \Z pass the PCRE_NOTEOL option to pcre[16|32]_exec()
687 or pcre[16|32]_dfa_exec()
688 \? pass the PCRE_NO_UTF[8|16|32]_CHECK option to
689 pcre[16|32]_exec() or pcre[16|32]_dfa_exec()
690 \>dd start the match at offset dd (optional "-"; then
691 any number of digits); this sets the startoffset
692 argument for pcre[16|32]_exec() or
693 pcre[16|32]_dfa_exec()
694 \<cr> pass the PCRE_NEWLINE_CR option to pcre[16|32]_exec()
695 or pcre[16|32]_dfa_exec()
696 \<lf> pass the PCRE_NEWLINE_LF option to pcre[16|32]_exec()
697 or pcre[16|32]_dfa_exec()
698 \<crlf> pass the PCRE_NEWLINE_CRLF option to pcre[16|32]_exec()
699 or pcre[16|32]_dfa_exec()
700 \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre[16|32]_exec()
701 or pcre[16|32]_dfa_exec()
702 \<any> pass the PCRE_NEWLINE_ANY option to pcre[16|32]_exec()
703 or pcre[16|32]_dfa_exec()
705 The use of \x{hh...} is not dependent on the use of the /8 modifier on
706 the pattern. It is recognized always. There may be any number of hexa-
707 decimal digits inside the braces; invalid values provoke error mes-
708 sages.
710 Note that \xhh specifies one byte rather than one character in UTF-8
711 mode; this makes it possible to construct invalid UTF-8 sequences for
712 testing purposes. On the other hand, \x{hh} is interpreted as a UTF-8
713 character in UTF-8 mode, generating more than one byte if the value is
714 greater than 127. When testing the 8-bit library not in UTF-8 mode,
715 \x{hh} generates one byte for values less than 256, and causes an error
716 for greater values.
718 In UTF-16 mode, all 4-digit \x{hhhh} values are accepted. This makes it
719 possible to construct invalid UTF-16 sequences for testing purposes.
721 In UTF-32 mode, all 4- to 8-digit \x{...} values are accepted. This
722 makes it possible to construct invalid UTF-32 sequences for testing
723 purposes.
725 The escapes that specify line ending sequences are literal strings,
726 exactly as shown. No more than one newline setting should be present in
727 any data line.
729 A backslash followed by anything else just escapes the anything else.
730 If the very last character is a backslash, it is ignored. This gives a
731 way of passing an empty line as data, since a real empty line termi-
732 nates the data input.
734 The \J escape provides a way of setting the maximum stack size that is
735 used by the just-in-time optimization code. It is ignored if JIT opti-
736 mization is not being used. Providing a stack that is larger than the
737 default 32K is necessary only for very complicated patterns.
739 If \M is present, pcretest calls pcre[16|32]_exec() several times, with
740 different values in the match_limit and match_limit_recursion fields of
741 the pcre[16|32]_extra data structure, until it finds the minimum num-
742 bers for each parameter that allow pcre[16|32]_exec() to complete with-
743 out error. Because this is testing a specific feature of the normal
744 interpretive pcre[16|32]_exec() execution, the use of any JIT optimiza-
745 tion that might have been set up by the /S+ qualifier of -s+ option is
746 disabled.
748 The match_limit number is a measure of the amount of backtracking that
749 takes place, and checking it out can be instructive. For most simple
750 matches, the number is quite small, but for patterns with very large
751 numbers of matching possibilities, it can become large very quickly
752 with increasing length of subject string. The match_limit_recursion
753 number is a measure of how much stack (or, if PCRE is compiled with
754 NO_RECURSE, how much heap) memory is needed to complete the match
755 attempt.
757 When \O is used, the value specified may be higher or lower than the
758 size set by the -O command line option (or defaulted to 45); \O applies
759 only to the call of pcre[16|32]_exec() for the line in which it
760 appears.
762 If the /P modifier was present on the pattern, causing the POSIX wrap-
763 per API to be used, the only option-setting sequences that have any
764 effect are \B, \N, and \Z, causing REG_NOTBOL, REG_NOTEMPTY, and
765 REG_NOTEOL, respectively, to be passed to regexec().
770 By default, pcretest uses the standard PCRE matching function,
771 pcre[16|32]_exec() to match each data line. PCRE also supports an
772 alternative matching function, pcre[16|32]_dfa_test(), which operates
773 in a different way, and has some restrictions. The differences between
774 the two functions are described in the pcrematching documentation.
776 If a data line contains the \D escape sequence, or if the command line
777 contains the -dfa option, the alternative matching function is used.
778 This function finds all possible matches at a given point. If, however,
779 the \F escape sequence is present in the data line, it stops after the
780 first match is found. This is always the shortest possible match.
785 This section describes the output when the normal matching function,
786 pcre[16|32]_exec(), is being used.
788 When a match succeeds, pcretest outputs the list of captured substrings
789 that pcre[16|32]_exec() returns, starting with number 0 for the string
790 that matched the whole pattern. Otherwise, it outputs "No match" when
791 the return is PCRE_ERROR_NOMATCH, and "Partial match:" followed by the
792 partially matching substring when pcre[16|32]_exec() returns
793 PCRE_ERROR_PARTIAL. (Note that this is the entire substring that was
794 inspected during the partial match; it may include characters before
795 the actual match start if a lookbehind assertion, \K, \b, or \B was
796 involved.) For any other return, pcretest outputs the PCRE negative
797 error number and a short descriptive phrase. If the error is a failed
798 UTF string check, the offset of the start of the failing character and
799 the reason code are also output, provided that the size of the output
800 vector is at least two. Here is an example of an interactive pcretest
801 run.
803 $ pcretest
804 PCRE version 8.13 2011-04-30
806 re> /^abc(\d+)/
807 data> abc123
808 0: abc123
809 1: 123
810 data> xyz
811 No match
813 Unset capturing substrings that are not followed by one that is set are
814 not returned by pcre[16|32]_exec(), and are not shown by pcretest. In
815 the following example, there are two capturing substrings, but when the
816 first data line is matched, the second, unset substring is not shown.
817 An "internal" unset substring is shown as "<unset>", as for the second
818 data line.
820 re> /(a)|(b)/
821 data> a
822 0: a
823 1: a
824 data> b
825 0: b
826 1: <unset>
827 2: b
829 If the strings contain any non-printing characters, they are output as
830 \xhh escapes if the value is less than 256 and UTF mode is not set.
831 Otherwise they are output as \x{hh...} escapes. See below for the defi-
832 nition of non-printing characters. If the pattern has the /+ modifier,
833 the output for substring 0 is followed by the the rest of the subject
834 string, identified by "0+" like this:
836 re> /cat/+
837 data> cataract
838 0: cat
839 0+ aract
841 If the pattern has the /g or /G modifier, the results of successive
842 matching attempts are output in sequence, like this:
844 re> /\Bi(\w\w)/g
845 data> Mississippi
846 0: iss
847 1: ss
848 0: iss
849 1: ss
850 0: ipp
851 1: pp
853 "No match" is output only if the first match attempt fails. Here is an
854 example of a failure message (the offset 4 that is specified by \>4 is
855 past the end of the subject string):
857 re> /xyz/
858 data> xyz\>4
859 Error -24 (bad offset value)
861 If any of the sequences \C, \G, or \L are present in a data line that
862 is successfully matched, the substrings extracted by the convenience
863 functions are output with C, G, or L after the string number instead of
864 a colon. This is in addition to the normal full list. The string length
865 (that is, the return from the extraction function) is given in paren-
866 theses after each string for \C and \G.
868 Note that whereas patterns can be continued over several lines (a plain
869 ">" prompt is used for continuations), data lines may not. However new-
870 lines can be included in data by means of the \n escape (or \r, \r\n,
871 etc., depending on the newline sequence setting).
876 When the alternative matching function, pcre[16|32]_dfa_exec(), is used
877 (by means of the \D escape sequence or the -dfa command line option),
878 the output consists of a list of all the matches that start at the
879 first point in the subject where there is at least one match. For exam-
880 ple:
882 re> /(tang|tangerine|tan)/
883 data> yellow tangerine\D
884 0: tangerine
885 1: tang
886 2: tan
888 (Using the normal matching function on this data finds only "tang".)
889 The longest matching string is always given first (and numbered zero).
890 After a PCRE_ERROR_PARTIAL return, the output is "Partial match:", fol-
891 lowed by the partially matching substring. (Note that this is the
892 entire substring that was inspected during the partial match; it may
893 include characters before the actual match start if a lookbehind asser-
894 tion, \K, \b, or \B was involved.)
896 If /g is present on the pattern, the search for further matches resumes
897 at the end of the longest match. For example:
899 re> /(tang|tangerine|tan)/g
900 data> yellow tangerine and tangy sultana\D
901 0: tangerine
902 1: tang
903 2: tan
904 0: tang
905 1: tan
906 0: tan
908 Since the matching function does not support substring capture, the
909 escape sequences that are concerned with captured substrings are not
910 relevant.
915 When the alternative matching function has given the PCRE_ERROR_PARTIAL
916 return, indicating that the subject partially matched the pattern, you
917 can restart the match with additional subject data by means of the \R
918 escape sequence. For example:
920 re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
921 data> 23ja\P\D
922 Partial match: 23ja
923 data> n05\R\D
924 0: n05
926 For further information about partial matching, see the pcrepartial
927 documentation.
932 If the pattern contains any callout requests, pcretest's callout func-
933 tion is called during matching. This works with both matching func-
934 tions. By default, the called function displays the callout number, the
935 start and current positions in the text at the callout time, and the
936 next pattern item to be tested. For example:
938 --->pqrabcdef
939 0 ^ ^ \d
941 This output indicates that callout number 0 occurred for a match
942 attempt starting at the fourth character of the subject string, when
943 the pointer was at the seventh character of the data, and when the next
944 pattern item was \d. Just one circumflex is output if the start and
945 current positions are the same.
947 Callouts numbered 255 are assumed to be automatic callouts, inserted as
948 a result of the /C pattern modifier. In this case, instead of showing
949 the callout number, the offset in the pattern, preceded by a plus, is
950 output. For example:
952 re> /\d?[A-E]\*/C
953 data> E*
954 --->E*
955 +0 ^ \d?
956 +3 ^ [A-E]
957 +8 ^^ \*
958 +10 ^ ^
959 0: E*
961 If a pattern contains (*MARK) items, an additional line is output when-
962 ever a change of latest mark is passed to the callout function. For
963 example:
965 re> /a(*MARK:X)bc/C
966 data> abc
967 --->abc
968 +0 ^ a
969 +1 ^^ (*MARK:X)
970 +10 ^^ b
971 Latest Mark: X
972 +11 ^ ^ c
973 +12 ^ ^
974 0: abc
976 The mark changes between matching "a" and "b", but stays the same for
977 the rest of the match, so nothing more is output. If, as a result of
978 backtracking, the mark reverts to being unset, the text "<unset>" is
979 output.
981 The callout function in pcretest returns zero (carry on matching) by
982 default, but you can use a \C item in a data line (as described above)
983 to change this and other parameters of the callout.
985 Inserting callouts can be helpful when using pcretest to check compli-
986 cated regular expressions. For further information about callouts, see
987 the pcrecallout documentation.
992 When pcretest is outputting text in the compiled version of a pattern,
993 bytes other than 32-126 are always treated as non-printing characters
994 are are therefore shown as hex escapes.
996 When pcretest is outputting text that is a matched part of a subject
997 string, it behaves in the same way, unless a different locale has been
998 set for the pattern (using the /L modifier). In this case, the
999 isprint() function to distinguish printing and non-printing characters.
1004 The facilities described in this section are not available when the
1005 POSIX interface to PCRE is being used, that is, when the /P pattern
1006 modifier is specified.
1008 When the POSIX interface is not in use, you can cause pcretest to write
1009 a compiled pattern to a file, by following the modifiers with > and a
1010 file name. For example:
1012 /pattern/im >/some/file
1014 See the pcreprecompile documentation for a discussion about saving and
1015 re-using compiled patterns. Note that if the pattern was successfully
1016 studied with JIT optimization, the JIT data cannot be saved.
1018 The data that is written is binary. The first eight bytes are the
1019 length of the compiled pattern data followed by the length of the
1020 optional study data, each written as four bytes in big-endian order
1021 (most significant byte first). If there is no study data (either the
1022 pattern was not studied, or studying did not return any data), the sec-
1023 ond length is zero. The lengths are followed by an exact copy of the
1024 compiled pattern. If there is additional study data, this (excluding
1025 any JIT data) follows immediately after the compiled pattern. After
1026 writing the file, pcretest expects to read a new pattern.
1028 A saved pattern can be reloaded into pcretest by specifying < and a
1029 file name instead of a pattern. There must be no space between < and
1030 the file name, which must not contain a < character, as otherwise
1031 pcretest will interpret the line as a pattern delimited by < charac-
1032 ters. For example:
1034 re> </some/file
1035 Compiled pattern loaded from /some/file
1036 No study data
1038 If the pattern was previously studied with the JIT optimization, the
1039 JIT information cannot be saved and restored, and so is lost. When the
1040 pattern has been loaded, pcretest proceeds to read data lines in the
1041 usual way.
1043 You can copy a file written by pcretest to a different host and reload
1044 it there, even if the new host has opposite endianness to the one on
1045 which the pattern was compiled. For example, you can compile on an i86
1046 machine and run on a SPARC machine. When a pattern is reloaded on a
1047 host with different endianness, the confirmation message is changed to:
1049 Compiled pattern (byte-inverted) loaded from /some/file
1051 The test suite contains some saved pre-compiled patterns with different
1052 endianness. These are reloaded using "<!" instead of just "<". This
1053 suppresses the "(byte-inverted)" text so that the output is the same on
1054 all hosts. It also forces debugging output once the pattern has been
1055 reloaded.
1057 File names for saving and reloading can be absolute or relative, but
1058 note that the shell facility of expanding a file name that starts with
1059 a tilde (~) is not available.
1061 The ability to save and reload files in pcretest is intended for test-
1062 ing and experimentation. It is not intended for production use because
1063 only a single pattern can be written to a file. Furthermore, there is
1064 no facility for supplying custom character tables for use with a
1065 reloaded pattern. If the original pattern was compiled with custom
1066 tables, an attempt to match a subject string using a reloaded pattern
1067 is likely to cause pcretest to crash. Finally, if you attempt to load
1068 a file that is not in the correct format, the result is undefined.
1073 pcre(3), pcre16(3), pcre32(3), pcreapi(3), pcrecallout(3), pcrejit,
1074 pcrematching(3), pcrepartial(d), pcrepattern(3), pcreprecompile(3).
1079 Philip Hazel
1080 University Computing Service
1081 Cambridge CB2 3QH, England.
1086 Last updated: 09 February 2014
1087 Copyright (c) 1997-2014 University of Cambridge.


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