1PCRETEST(1) General Commands Manual PCRETEST(1)
2
6 pcretest - a program for testing Perl-compatible regular expressions.
7
9 pcretest [options] [input file [output file]]
11 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.
18 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.
23 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.
30
32 Input to pcretest is processed line by line, either by calling the C
34 library's fgets() function, or via the libreadline library (see below).
35 In Unix-like environments, fgets() treats any bytes other than newline
36 as data characters. However, in some Windows environments character 26
37 (hex 1A) causes an immediate end of file, and no further data is read.
38 For maximum portability, therefore, it is safest to use only ASCII
39 characters in pcretest input files.
40 The input is processed using using C's string functions, so must not
42 contain binary zeroes, even though in Unix-like environments, fgets()
43 treats any bytes other than newline as data characters.
44
46 From release 8.30, two separate PCRE libraries can be built. The origi‐
48 nal one supports 8-bit character strings, whereas the newer 16-bit
49 library supports character strings encoded in 16-bit units. From
50 release 8.32, a third library can be built, supporting character
51 strings encoded in 32-bit units. The pcretest program can be used to
52 test all three libraries. However, it is itself still an 8-bit program,
53 reading 8-bit input and writing 8-bit output. When testing the 16-bit
54 or 32-bit library, the patterns and data strings are converted to 16-
55 or 32-bit format before being passed to the PCRE library functions.
56 Results are converted to 8-bit for output.
57 References to functions and structures of the form pcre[16|32]_xx below
59 mean "pcre_xx when using the 8-bit library, pcre16_xx when using the
60 16-bit library, or pcre32_xx when using the 32-bit library".
61
63 -8 If the 8-bit library has been built, this option causes it to
65 be used (this is the default). If the 8-bit library has not
66 been built, this option causes an error.
67 -16 If the 16-bit library has been built, this option causes it
69 to be used. If only the 16-bit library has been built, this
70 is the default. If the 16-bit library has not been built,
71 this option causes an error.
72 -32 If the 32-bit library has been built, this option causes it
74 to be used. If only the 32-bit library has been built, this
75 is the default. If the 32-bit library has not been built,
76 this option causes an error.
77 -b Behave as if each pattern has the /B (show byte code) modi‐
79 fier; the internal form is output after compilation.
80 -C Output the version number of the PCRE library, and all avail‐
82 able information about the optional features that are
83 included, and then exit with zero exit code. All other
84 options are ignored.
85 -C option Output information about a specific build-time option, then
87 exit. This functionality is intended for use in scripts such
88 as RunTest. The following options output the value and set
89 the exit code as indicated:
90 ebcdic-nl the code for LF (= NL) in an EBCDIC environment:
92 0x15 or 0x25
93 0 if used in an ASCII environment
94 exit code is always 0
95 linksize the configured internal link size (2, 3, or 4)
96 exit code is set to the link size
97 newline the default newline setting:
98 CR, LF, CRLF, ANYCRLF, or ANY
99 exit code is always 0
100 bsr the default setting for what \R matches:
101 ANYCRLF or ANY
102 exit code is always 0
103 The following options output 1 for true or 0 for false, and
105 set the exit code to the same value:
106 ebcdic compiled for an EBCDIC environment
108 jit just-in-time support is available
109 pcre16 the 16-bit library was built
110 pcre32 the 32-bit library was built
111 pcre8 the 8-bit library was built
112 ucp Unicode property support is available
113 utf UTF-8 and/or UTF-16 and/or UTF-32 support
114 is available
115 If an unknown option is given, an error message is output;
117 the exit code is 0.
118 -d Behave as if each pattern has the /D (debug) modifier; the
120 internal form and information about the compiled pattern is
121 output after compilation; -d is equivalent to -b -i.
122 -dfa Behave as if each data line contains the \D escape sequence;
124 this causes the alternative matching function,
125 pcre[16|32]_dfa_exec(), to be used instead of the standard
126 pcre[16|32]_exec() function (more detail is given below).
127 -help Output a brief summary these options and then exit.
129 -i Behave as if each pattern has the /I modifier; information
131 about the compiled pattern is given after compilation.
132 -M Behave as if each data line contains the \M escape sequence;
134 this causes PCRE to discover the minimum MATCH_LIMIT and
135 MATCH_LIMIT_RECURSION settings by calling pcre[16|32]_exec()
136 repeatedly with different limits.
137 -m Output the size of each compiled pattern after it has been
139 compiled. This is equivalent to adding /M to each regular
140 expression. The size is given in bytes for both libraries.
141 -O Behave as if each pattern has the /O modifier, that is dis‐
143 able auto-possessification for all patterns.
144 -o osize Set the number of elements in the output vector that is used
146 when calling pcre[16|32]_exec() or pcre[16|32]_dfa_exec() to
147 be osize. The default value is 45, which is enough for 14
148 capturing subexpressions for pcre[16|32]_exec() or 22 differ‐
149 ent matches for pcre[16|32]_dfa_exec(). The vector size can
150 be changed for individual matching calls by including \O in
151 the data line (see below).
152 -p Behave as if each pattern has the /P modifier; the POSIX
154 wrapper API is used to call PCRE. None of the other options
155 has any effect when -p is set. This option can be used only
156 with the 8-bit library.
157 -q Do not output the version number of pcretest at the start of
159 execution.
160 -S size On Unix-like systems, set the size of the run-time stack to
162 size megabytes.
163 -s or -s+ Behave as if each pattern has the /S modifier; in other
165 words, force each pattern to be studied. If -s+ is used, all
166 the JIT compile options are passed to pcre[16|32]_study(),
167 causing just-in-time optimization to be set up if it is
168 available, for both full and partial matching. Specific JIT
169 compile options can be selected by following -s+ with a digit
170 in the range 1 to 7, which selects the JIT compile modes as
171 follows:
172 1 normal match only
174 2 soft partial match only
175 3 normal match and soft partial match
176 4 hard partial match only
177 6 soft and hard partial match
178 7 all three modes (default)
179 If -s++ is used instead of -s+ (with or without a following
181 digit), the text "(JIT)" is added to the first output line
182 after a match or no match when JIT-compiled code was actually
183 used.
184 Note that there are pattern options that can override -s,
186 either specifying no studying at all, or suppressing JIT com‐
187 pilation.
188 If the /I or /D option is present on a pattern (requesting
190 output about the compiled pattern), information about the
191 result of studying is not included when studying is caused
192 only by -s and neither -i nor -d is present on the command
193 line. This behaviour means that the output from tests that
194 are run with and without -s should be identical, except when
195 options that output information about the actual running of a
196 match are set.
197 The -M, -t, and -tm options, which give information about
199 resources used, are likely to produce different output with
200 and without -s. Output may also differ if the /C option is
201 present on an individual pattern. This uses callouts to trace
202 the the matching process, and this may be different between
203 studied and non-studied patterns. If the pattern contains
204 (*MARK) items there may also be differences, for the same
205 reason. The -s command line option can be overridden for spe‐
206 cific patterns that should never be studied (see the /S pat‐
207 tern modifier below).
208 -t Run each compile, study, and match many times with a timer,
210 and output the resulting times per compile, study, or match
211 (in milliseconds). Do not set -m with -t, because you will
212 then get the size output a zillion times, and the timing will
213 be distorted. You can control the number of iterations that
214 are used for timing by following -t with a number (as a sepa‐
215 rate item on the command line). For example, "-t 1000" iter‐
216 ates 1000 times. The default is to iterate 500000 times.
217 -tm This is like -t except that it times only the matching phase,
219 not the compile or study phases.
220 -T -TM These behave like -t and -tm, but in addition, at the end of
222 a run, the total times for all compiles, studies, and matches
223 are output.
224
226 If pcretest is given two filename arguments, it reads from the first
228 and writes to the second. If it is given only one filename argument, it
229 reads from that file and writes to stdout. Otherwise, it reads from
230 stdin and writes to stdout, and prompts for each line of input, using
231 "re>" to prompt for regular expressions, and "data>" to prompt for data
232 lines.
233 When pcretest is built, a configuration option can specify that it
235 should be linked with the libreadline library. When this is done, if
236 the input is from a terminal, it is read using the readline() function.
237 This provides line-editing and history facilities. The output from the
238 -help option states whether or not readline() will be used.
239 The program handles any number of sets of input on a single input file.
241 Each set starts with a regular expression, and continues with any num‐
242 ber of data lines to be matched against that pattern.
243 Each data line is matched separately and independently. If you want to
245 do multi-line matches, you have to use the \n escape sequence (or \r or
246 \r\n, etc., depending on the newline setting) in a single line of input
247 to encode the newline sequences. There is no limit on the length of
248 data lines; the input buffer is automatically extended if it is too
249 small.
250 An empty line signals the end of the data lines, at which point a new
252 regular expression is read. The regular expressions are given enclosed
253 in any non-alphanumeric delimiters other than backslash, for example:
254 /(a|bc)x+yz/
256 White space before the initial delimiter is ignored. A regular expres‐
258 sion may be continued over several input lines, in which case the new‐
259 line characters are included within it. It is possible to include the
260 delimiter within the pattern by escaping it, for example
261 /abc\/def/
263 If you do so, the escape and the delimiter form part of the pattern,
265 but since delimiters are always non-alphanumeric, this does not affect
266 its interpretation. If the terminating delimiter is immediately fol‐
267 lowed by a backslash, for example,
268 /abc/\
270 then a backslash is added to the end of the pattern. This is done to
272 provide a way of testing the error condition that arises if a pattern
273 finishes with a backslash, because
274 /abc\/
276 is interpreted as the first line of a pattern that starts with "abc/",
278 causing pcretest to read the next line as a continuation of the regular
279 expression.
280
282 A pattern may be followed by any number of modifiers, which are mostly
284 single characters, though some of these can be qualified by further
285 characters. Following Perl usage, these are referred to below as, for
286 example, "the /i modifier", even though the delimiter of the pattern
287 need not always be a slash, and no slash is used when writing modi‐
288 fiers. White space may appear between the final pattern delimiter and
289 the first modifier, and between the modifiers themselves. For refer‐
290 ence, here is a complete list of modifiers. They fall into several
291 groups that are described in detail in the following sections.
292 /8 set UTF mode
294 /9 set PCRE_NEVER_UTF (locks out UTF mode)
295 /? disable UTF validity check
296 /+ show remainder of subject after match
297 /= show all captures (not just those that are set)
298 /A set PCRE_ANCHORED
300 /B show compiled code
301 /C set PCRE_AUTO_CALLOUT
302 /D same as /B plus /I
303 /E set PCRE_DOLLAR_ENDONLY
304 /F flip byte order in compiled pattern
305 /f set PCRE_FIRSTLINE
306 /G find all matches (shorten string)
307 /g find all matches (use startoffset)
308 /I show information about pattern
309 /i set PCRE_CASELESS
310 /J set PCRE_DUPNAMES
311 /K show backtracking control names
312 /L set locale
313 /M show compiled memory size
314 /m set PCRE_MULTILINE
315 /N set PCRE_NO_AUTO_CAPTURE
316 /O set PCRE_NO_AUTO_POSSESS
317 /P use the POSIX wrapper
318 /Q test external stack check function
319 /S study the pattern after compilation
320 /s set PCRE_DOTALL
321 /T select character tables
322 /U set PCRE_UNGREEDY
323 /W set PCRE_UCP
324 /X set PCRE_EXTRA
325 /x set PCRE_EXTENDED
326 /Y set PCRE_NO_START_OPTIMIZE
327 /Z don't show lengths in /B output
328 /<any> set PCRE_NEWLINE_ANY
330 /<anycrlf> set PCRE_NEWLINE_ANYCRLF
331 /<cr> set PCRE_NEWLINE_CR
332 /<crlf> set PCRE_NEWLINE_CRLF
333 /<lf> set PCRE_NEWLINE_LF
334 /<bsr_anycrlf> set PCRE_BSR_ANYCRLF
335 /<bsr_unicode> set PCRE_BSR_UNICODE
336 /<JS> set PCRE_JAVASCRIPT_COMPAT
337 Perl-compatible modifiers
340 The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,
342 PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when
343 pcre[16|32]_compile() is called. These four modifier letters have the
344 same effect as they do in Perl. For example:
345 /caseless/i
347 Modifiers for other PCRE options
350 The following table shows additional modifiers for setting PCRE com‐
352 pile-time options that do not correspond to anything in Perl:
353 /8 PCRE_UTF8 ) when using the 8-bit
355 /? PCRE_NO_UTF8_CHECK ) library
356 /8 PCRE_UTF16 ) when using the 16-bit
358 /? PCRE_NO_UTF16_CHECK ) library
359 /8 PCRE_UTF32 ) when using the 32-bit
361 /? PCRE_NO_UTF32_CHECK ) library
362 /9 PCRE_NEVER_UTF
364 /A PCRE_ANCHORED
365 /C PCRE_AUTO_CALLOUT
366 /E PCRE_DOLLAR_ENDONLY
367 /f PCRE_FIRSTLINE
368 /J PCRE_DUPNAMES
369 /N PCRE_NO_AUTO_CAPTURE
370 /O PCRE_NO_AUTO_POSSESS
371 /U PCRE_UNGREEDY
372 /W PCRE_UCP
373 /X PCRE_EXTRA
374 /Y PCRE_NO_START_OPTIMIZE
375 /<any> PCRE_NEWLINE_ANY
376 /<anycrlf> PCRE_NEWLINE_ANYCRLF
377 /<cr> PCRE_NEWLINE_CR
378 /<crlf> PCRE_NEWLINE_CRLF
379 /<lf> PCRE_NEWLINE_LF
380 /<bsr_anycrlf> PCRE_BSR_ANYCRLF
381 /<bsr_unicode> PCRE_BSR_UNICODE
382 /<JS> PCRE_JAVASCRIPT_COMPAT
383 The modifiers that are enclosed in angle brackets are literal strings
385 as shown, including the angle brackets, but the letters within can be
386 in either case. This example sets multiline matching with CRLF as the
387 line ending sequence:
388 /^abc/m<CRLF>
390 As well as turning on the PCRE_UTF8/16/32 option, the /8 modifier
392 causes all non-printing characters in output strings to be printed
393 using the \x{hh...} notation. Otherwise, those less than 0x100 are out‐
394 put in hex without the curly brackets.
395 Full details of the PCRE options are given in the pcreapi documenta‐
397 tion.
398 Finding all matches in a string
400 Searching for all possible matches within each subject string can be
402 requested by the /g or /G modifier. After finding a match, PCRE is
403 called again to search the remainder of the subject string. The differ‐
404 ence between /g and /G is that the former uses the startoffset argument
405 to pcre[16|32]_exec() to start searching at a new point within the
406 entire string (which is in effect what Perl does), whereas the latter
407 passes over a shortened substring. This makes a difference to the
408 matching process if the pattern begins with a lookbehind assertion
409 (including \b or \B).
410 If any call to pcre[16|32]_exec() in a /g or /G sequence matches an
412 empty string, the next call is done with the PCRE_NOTEMPTY_ATSTART and
413 PCRE_ANCHORED flags set in order to search for another, non-empty,
414 match at the same point. If this second match fails, the start offset
415 is advanced, and the normal match is retried. This imitates the way
416 Perl handles such cases when using the /g modifier or the split() func‐
417 tion. Normally, the start offset is advanced by one character, but if
418 the newline convention recognizes CRLF as a newline, and the current
419 character is CR followed by LF, an advance of two is used.
420 Other modifiers
422 There are yet more modifiers for controlling the way pcretest operates.
424 The /+ modifier requests that as well as outputting the substring that
426 matched the entire pattern, pcretest should in addition output the
427 remainder of the subject string. This is useful for tests where the
428 subject contains multiple copies of the same substring. If the + modi‐
429 fier appears twice, the same action is taken for captured substrings.
430 In each case the remainder is output on the following line with a plus
431 character following the capture number. Note that this modifier must
432 not immediately follow the /S modifier because /S+ and /S++ have other
433 meanings.
434 The /= modifier requests that the values of all potential captured
436 parentheses be output after a match. By default, only those up to the
437 highest one actually used in the match are output (corresponding to the
438 return code from pcre[16|32]_exec()). Values in the offsets vector cor‐
439 responding to higher numbers should be set to -1, and these are output
440 as "<unset>". This modifier gives a way of checking that this is hap‐
441 pening.
442 The /B modifier is a debugging feature. It requests that pcretest out‐
444 put a representation of the compiled code after compilation. Normally
445 this information contains length and offset values; however, if /Z is
446 also present, this data is replaced by spaces. This is a special fea‐
447 ture for use in the automatic test scripts; it ensures that the same
448 output is generated for different internal link sizes.
449 The /D modifier is a PCRE debugging feature, and is equivalent to /BI,
451 that is, both the /B and the /I modifiers.
452 The /F modifier causes pcretest to flip the byte order of the 2-byte
454 and 4-byte fields in the compiled pattern. This facility is for testing
455 the feature in PCRE that allows it to execute patterns that were com‐
456 piled on a host with a different endianness. This feature is not avail‐
457 able when the POSIX interface to PCRE is being used, that is, when the
458 /P pattern modifier is specified. See also the section about saving and
459 reloading compiled patterns below.
460 The /I modifier requests that pcretest output information about the
462 compiled pattern (whether it is anchored, has a fixed first character,
463 and so on). It does this by calling pcre[16|32]_fullinfo() after com‐
464 piling a pattern. If the pattern is studied, the results of that are
465 also output. In this output, the word "char" means a non-UTF character,
466 that is, the value of a single data item (8-bit, 16-bit, or 32-bit,
467 depending on the library that is being tested).
468 The /K modifier requests pcretest to show names from backtracking con‐
470 trol verbs that are returned from calls to pcre[16|32]_exec(). It
471 causes pcretest to create a pcre[16|32]_extra block if one has not
472 already been created by a call to pcre[16|32]_study(), and to set the
473 PCRE_EXTRA_MARK flag and the mark field within it, every time that
474 pcre[16|32]_exec() is called. If the variable that the mark field
475 points to is non-NULL for a match, non-match, or partial match,
476 pcretest prints the string to which it points. For a match, this is
477 shown on a line by itself, tagged with "MK:". For a non-match it is
478 added to the message.
479 The /L modifier must be followed directly by the name of a locale, for
481 example,
482 /pattern/Lfr_FR
484 For this reason, it must be the last modifier. The given locale is set,
486 pcre[16|32]_maketables() is called to build a set of character tables
487 for the locale, and this is then passed to pcre[16|32]_compile() when
488 compiling the regular expression. Without an /L (or /T) modifier, NULL
489 is passed as the tables pointer; that is, /L applies only to the
490 expression on which it appears.
491 The /M modifier causes the size in bytes of the memory block used to
493 hold the compiled pattern to be output. This does not include the size
494 of the pcre[16|32] block; it is just the actual compiled data. If the
495 pattern is successfully studied with the PCRE_STUDY_JIT_COMPILE option,
496 the size of the JIT compiled code is also output.
497 The /Q modifier is used to test the use of pcre_stack_guard. It must be
499 followed by '0' or '1', specifying the return code to be given from an
500 external function that is passed to PCRE and used for stack checking
501 during compilation (see the pcreapi documentation for details).
502 The /S modifier causes pcre[16|32]_study() to be called after the
504 expression has been compiled, and the results used when the expression
505 is matched. There are a number of qualifying characters that may follow
506 /S. They may appear in any order.
507 If /S is followed by an exclamation mark, pcre[16|32]_study() is called
509 with the PCRE_STUDY_EXTRA_NEEDED option, causing it always to return a
510 pcre_extra block, even when studying discovers no useful information.
511 If /S is followed by a second S character, it suppresses studying, even
513 if it was requested externally by the -s command line option. This
514 makes it possible to specify that certain patterns are always studied,
515 and others are never studied, independently of -s. This feature is used
516 in the test files in a few cases where the output is different when the
517 pattern is studied.
518 If the /S modifier is followed by a + character, the call to
520 pcre[16|32]_study() is made with all the JIT study options, requesting
521 just-in-time optimization support if it is available, for both normal
522 and partial matching. If you want to restrict the JIT compiling modes,
523 you can follow /S+ with a digit in the range 1 to 7:
524 1 normal match only
526 2 soft partial match only
527 3 normal match and soft partial match
528 4 hard partial match only
529 6 soft and hard partial match
530 7 all three modes (default)
531 If /S++ is used instead of /S+ (with or without a following digit), the
533 text "(JIT)" is added to the first output line after a match or no
534 match when JIT-compiled code was actually used.
535 Note that there is also an independent /+ modifier; it must not be
537 given immediately after /S or /S+ because this will be misinterpreted.
538 If JIT studying is successful, the compiled JIT code will automatically
540 be used when pcre[16|32]_exec() is run, except when incompatible run-
541 time options are specified. For more details, see the pcrejit documen‐
542 tation. See also the \J escape sequence below for a way of setting the
543 size of the JIT stack.
544 Finally, if /S is followed by a minus character, JIT compilation is
546 suppressed, even if it was requested externally by the -s command line
547 option. This makes it possible to specify that JIT is never to be used
548 for certain patterns.
549 The /T modifier must be followed by a single digit. It causes a spe‐
551 cific set of built-in character tables to be passed to pcre[16|32]_com‐
552 pile(). It is used in the standard PCRE tests to check behaviour with
553 different character tables. The digit specifies the tables as follows:
554 0 the default ASCII tables, as distributed in
556 pcre_chartables.c.dist
557 1 a set of tables defining ISO 8859 characters
558 In table 1, some characters whose codes are greater than 128 are iden‐
560 tified as letters, digits, spaces, etc.
561 Using the POSIX wrapper API
563 The /P modifier causes pcretest to call PCRE via the POSIX wrapper API
565 rather than its native API. This supports only the 8-bit library. When
566 /P is set, the following modifiers set options for the regcomp() func‐
567 tion:
568 /i REG_ICASE
570 /m REG_NEWLINE
571 /N REG_NOSUB
572 /s REG_DOTALL )
573 /U REG_UNGREEDY ) These options are not part of
574 /W REG_UCP ) the POSIX standard
575 /8 REG_UTF8 )
576 The /+ modifier works as described above. All other modifiers are
578 ignored.
579 Locking out certain modifiers
581 PCRE can be compiled with or without support for certain features such
583 as UTF-8/16/32 or Unicode properties. Accordingly, the standard tests
584 are split up into a number of different files that are selected for
585 running depending on which features are available. When updating the
586 tests, it is all too easy to put a new test into the wrong file by mis‐
587 take; for example, to put a test that requires UTF support into a file
588 that is used when it is not available. To help detect such mistakes as
589 early as possible, there is a facility for locking out specific modi‐
590 fiers. If an input line for pcretest starts with the string "< forbid "
591 the following sequence of characters is taken as a list of forbidden
592 modifiers. For example, in the test files that must not use UTF or Uni‐
593 code property support, this line appears:
594 < forbid 8W
596 This locks out the /8 and /W modifiers. An immediate error is given if
598 they are subsequently encountered. If the character string contains <
599 but not >, all the multi-character modifiers that begin with < are
600 locked out. Otherwise, such modifiers must be explicitly listed, for
601 example:
602 < forbid <JS><cr>
604 There must be a single space between < and "forbid" for this feature to
606 be recognised. If there is not, the line is interpreted either as a
607 request to re-load a pre-compiled pattern (see "SAVING AND RELOADING
608 COMPILED PATTERNS" below) or, if there is a another < character, as a
609 pattern that uses < as its delimiter.
610
612 Before each data line is passed to pcre[16|32]_exec(), leading and
614 trailing white space is removed, and it is then scanned for \ escapes.
615 Some of these are pretty esoteric features, intended for checking out
616 some of the more complicated features of PCRE. If you are just testing
617 "ordinary" regular expressions, you probably don't need any of these.
618 The following escapes are recognized:
619 \a alarm (BEL, \x07)
621 \b backspace (\x08)
622 \e escape (\x27)
623 \f form feed (\x0c)
624 \n newline (\x0a)
625 \qdd set the PCRE_MATCH_LIMIT limit to dd
626 (any number of digits)
627 \r carriage return (\x0d)
628 \t tab (\x09)
629 \v vertical tab (\x0b)
630 \nnn octal character (up to 3 octal digits); always
631 a byte unless > 255 in UTF-8 or 16-bit or 32-bit mode
632 \o{dd...} octal character (any number of octal digits}
633 \xhh hexadecimal byte (up to 2 hex digits)
634 \x{hh...} hexadecimal character (any number of hex digits)
635 \A pass the PCRE_ANCHORED option to pcre[16|32]_exec()
636 or pcre[16|32]_dfa_exec()
637 \B pass the PCRE_NOTBOL option to pcre[16|32]_exec()
638 or pcre[16|32]_dfa_exec()
639 \Cdd call pcre[16|32]_copy_substring() for substring dd
640 after a successful match (number less than 32)
641 \Cname call pcre[16|32]_copy_named_substring() for substring
642 "name" after a successful match (name terminated
643 by next non alphanumeric character)
644 \C+ show the current captured substrings at callout
645 time
646 \C- do not supply a callout function
647 \C!n return 1 instead of 0 when callout number n is
648 reached
649 \C!n!m return 1 instead of 0 when callout number n is
650 reached for the nth time
651 \C*n pass the number n (may be negative) as callout
652 data; this is used as the callout return value
653 \D use the pcre[16|32]_dfa_exec() match function
654 \F only shortest match for pcre[16|32]_dfa_exec()
655 \Gdd call pcre[16|32]_get_substring() for substring dd
656 after a successful match (number less than 32)
657 \Gname call pcre[16|32]_get_named_substring() for substring
658 "name" after a successful match (name terminated
659 by next non-alphanumeric character)
660 \Jdd set up a JIT stack of dd kilobytes maximum (any
661 number of digits)
662 \L call pcre[16|32]_get_substringlist() after a
663 successful match
664 \M discover the minimum MATCH_LIMIT and
665 MATCH_LIMIT_RECURSION settings
666 \N pass the PCRE_NOTEMPTY option to pcre[16|32]_exec()
667 or pcre[16|32]_dfa_exec(); if used twice, pass the
668 PCRE_NOTEMPTY_ATSTART option
669 \Odd set the size of the output vector passed to
670 pcre[16|32]_exec() to dd (any number of digits)
671 \P pass the PCRE_PARTIAL_SOFT option to pcre[16|32]_exec()
672 or pcre[16|32]_dfa_exec(); if used twice, pass the
673 PCRE_PARTIAL_HARD option
674 \Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd
675 (any number of digits)
676 \R pass the PCRE_DFA_RESTART option to pcre[16|32]_dfa_exec()
677 \S output details of memory get/free calls during matching
678 \Y pass the PCRE_NO_START_OPTIMIZE option to
679 pcre[16|32]_exec()
680 or pcre[16|32]_dfa_exec()
681 \Z pass the PCRE_NOTEOL option to pcre[16|32]_exec()
682 or pcre[16|32]_dfa_exec()
683 \? pass the PCRE_NO_UTF[8|16|32]_CHECK option to
684 pcre[16|32]_exec() or pcre[16|32]_dfa_exec()
685 \>dd start the match at offset dd (optional "-"; then
686 any number of digits); this sets the startoffset
687 argument for pcre[16|32]_exec() or
688 pcre[16|32]_dfa_exec()
689 \<cr> pass the PCRE_NEWLINE_CR option to pcre[16|32]_exec()
690 or pcre[16|32]_dfa_exec()
691 \<lf> pass the PCRE_NEWLINE_LF option to pcre[16|32]_exec()
692 or pcre[16|32]_dfa_exec()
693 \<crlf> pass the PCRE_NEWLINE_CRLF option to pcre[16|32]_exec()
694 or pcre[16|32]_dfa_exec()
695 \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre[16|32]_exec()
696 or pcre[16|32]_dfa_exec()
697 \<any> pass the PCRE_NEWLINE_ANY option to pcre[16|32]_exec()
698 or pcre[16|32]_dfa_exec()
699 The use of \x{hh...} is not dependent on the use of the /8 modifier on
701 the pattern. It is recognized always. There may be any number of hexa‐
702 decimal digits inside the braces; invalid values provoke error mes‐
703 sages.
704 Note that \xhh specifies one byte rather than one character in UTF-8
706 mode; this makes it possible to construct invalid UTF-8 sequences for
707 testing purposes. On the other hand, \x{hh} is interpreted as a UTF-8
708 character in UTF-8 mode, generating more than one byte if the value is
709 greater than 127. When testing the 8-bit library not in UTF-8 mode,
710 \x{hh} generates one byte for values less than 256, and causes an error
711 for greater values.
712 In UTF-16 mode, all 4-digit \x{hhhh} values are accepted. This makes it
714 possible to construct invalid UTF-16 sequences for testing purposes.
715 In UTF-32 mode, all 4- to 8-digit \x{...} values are accepted. This
717 makes it possible to construct invalid UTF-32 sequences for testing
718 purposes.
719 The escapes that specify line ending sequences are literal strings,
721 exactly as shown. No more than one newline setting should be present in
722 any data line.
723 A backslash followed by anything else just escapes the anything else.
725 If the very last character is a backslash, it is ignored. This gives a
726 way of passing an empty line as data, since a real empty line termi‐
727 nates the data input.
728 The \J escape provides a way of setting the maximum stack size that is
730 used by the just-in-time optimization code. It is ignored if JIT opti‐
731 mization is not being used. Providing a stack that is larger than the
732 default 32K is necessary only for very complicated patterns.
733 If \M is present, pcretest calls pcre[16|32]_exec() several times, with
735 different values in the match_limit and match_limit_recursion fields of
736 the pcre[16|32]_extra data structure, until it finds the minimum num‐
737 bers for each parameter that allow pcre[16|32]_exec() to complete with‐
738 out error. Because this is testing a specific feature of the normal
739 interpretive pcre[16|32]_exec() execution, the use of any JIT optimiza‐
740 tion that might have been set up by the /S+ qualifier of -s+ option is
741 disabled.
742 The match_limit number is a measure of the amount of backtracking that
744 takes place, and checking it out can be instructive. For most simple
745 matches, the number is quite small, but for patterns with very large
746 numbers of matching possibilities, it can become large very quickly
747 with increasing length of subject string. The match_limit_recursion
748 number is a measure of how much stack (or, if PCRE is compiled with
749 NO_RECURSE, how much heap) memory is needed to complete the match
750 attempt.
751 When \O is used, the value specified may be higher or lower than the
753 size set by the -O command line option (or defaulted to 45); \O applies
754 only to the call of pcre[16|32]_exec() for the line in which it
755 appears.
756 If the /P modifier was present on the pattern, causing the POSIX wrap‐
758 per API to be used, the only option-setting sequences that have any
759 effect are \B, \N, and \Z, causing REG_NOTBOL, REG_NOTEMPTY, and
760 REG_NOTEOL, respectively, to be passed to regexec().
761
763 By default, pcretest uses the standard PCRE matching function,
765 pcre[16|32]_exec() to match each data line. PCRE also supports an
766 alternative matching function, pcre[16|32]_dfa_test(), which operates
767 in a different way, and has some restrictions. The differences between
768 the two functions are described in the pcrematching documentation.
769 If a data line contains the \D escape sequence, or if the command line
771 contains the -dfa option, the alternative matching function is used.
772 This function finds all possible matches at a given point. If, however,
773 the \F escape sequence is present in the data line, it stops after the
774 first match is found. This is always the shortest possible match.
775
777 This section describes the output when the normal matching function,
779 pcre[16|32]_exec(), is being used.
780 When a match succeeds, pcretest outputs the list of captured substrings
782 that pcre[16|32]_exec() returns, starting with number 0 for the string
783 that matched the whole pattern. Otherwise, it outputs "No match" when
784 the return is PCRE_ERROR_NOMATCH, and "Partial match:" followed by the
785 partially matching substring when pcre[16|32]_exec() returns
786 PCRE_ERROR_PARTIAL. (Note that this is the entire substring that was
787 inspected during the partial match; it may include characters before
788 the actual match start if a lookbehind assertion, \K, \b, or \B was
789 involved.) For any other return, pcretest outputs the PCRE negative
790 error number and a short descriptive phrase. If the error is a failed
791 UTF string check, the offset of the start of the failing character and
792 the reason code are also output, provided that the size of the output
793 vector is at least two. Here is an example of an interactive pcretest
794 run.
795 $ pcretest
797 PCRE version 8.13 2011-04-30
798 re> /^abc(\d+)/
800 data> abc123
801 0: abc123
802 1: 123
803 data> xyz
804 No match
805 Unset capturing substrings that are not followed by one that is set are
807 not returned by pcre[16|32]_exec(), and are not shown by pcretest. In
808 the following example, there are two capturing substrings, but when the
809 first data line is matched, the second, unset substring is not shown.
810 An "internal" unset substring is shown as "<unset>", as for the second
811 data line.
812 re> /(a)|(b)/
814 data> a
815 0: a
816 1: a
817 data> b
818 0: b
819 1: <unset>
820 2: b
821 If the strings contain any non-printing characters, they are output as
823 \xhh escapes if the value is less than 256 and UTF mode is not set.
824 Otherwise they are output as \x{hh...} escapes. See below for the defi‐
825 nition of non-printing characters. If the pattern has the /+ modifier,
826 the output for substring 0 is followed by the the rest of the subject
827 string, identified by "0+" like this:
828 re> /cat/+
830 data> cataract
831 0: cat
832 0+ aract
833 If the pattern has the /g or /G modifier, the results of successive
835 matching attempts are output in sequence, like this:
836 re> /\Bi(\w\w)/g
838 data> Mississippi
839 0: iss
840 1: ss
841 0: iss
842 1: ss
843 0: ipp
844 1: pp
845 "No match" is output only if the first match attempt fails. Here is an
847 example of a failure message (the offset 4 that is specified by \>4 is
848 past the end of the subject string):
849 re> /xyz/
851 data> xyz\>4
852 Error -24 (bad offset value)
853 If any of the sequences \C, \G, or \L are present in a data line that
855 is successfully matched, the substrings extracted by the convenience
856 functions are output with C, G, or L after the string number instead of
857 a colon. This is in addition to the normal full list. The string length
858 (that is, the return from the extraction function) is given in paren‐
859 theses after each string for \C and \G.
860 Note that whereas patterns can be continued over several lines (a plain
862 ">" prompt is used for continuations), data lines may not. However new‐
863 lines can be included in data by means of the \n escape (or \r, \r\n,
864 etc., depending on the newline sequence setting).
865
867 When the alternative matching function, pcre[16|32]_dfa_exec(), is used
869 (by means of the \D escape sequence or the -dfa command line option),
870 the output consists of a list of all the matches that start at the
871 first point in the subject where there is at least one match. For exam‐
872 ple:
873 re> /(tang|tangerine|tan)/
875 data> yellow tangerine\D
876 0: tangerine
877 1: tang
878 2: tan
879 (Using the normal matching function on this data finds only "tang".)
881 The longest matching string is always given first (and numbered zero).
882 After a PCRE_ERROR_PARTIAL return, the output is "Partial match:", fol‐
883 lowed by the partially matching substring. (Note that this is the
884 entire substring that was inspected during the partial match; it may
885 include characters before the actual match start if a lookbehind asser‐
886 tion, \K, \b, or \B was involved.)
887 If /g is present on the pattern, the search for further matches resumes
889 at the end of the longest match. For example:
890 re> /(tang|tangerine|tan)/g
892 data> yellow tangerine and tangy sultana\D
893 0: tangerine
894 1: tang
895 2: tan
896 0: tang
897 1: tan
898 0: tan
899 Since the matching function does not support substring capture, the
901 escape sequences that are concerned with captured substrings are not
902 relevant.
903
905 When the alternative matching function has given the PCRE_ERROR_PARTIAL
907 return, indicating that the subject partially matched the pattern, you
908 can restart the match with additional subject data by means of the \R
909 escape sequence. For example:
910 re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
912 data> 23ja\P\D
913 Partial match: 23ja
914 data> n05\R\D
915 0: n05
916 For further information about partial matching, see the pcrepartial
918 documentation.
919
921 If the pattern contains any callout requests, pcretest's callout func‐
923 tion is called during matching. This works with both matching func‐
924 tions. By default, the called function displays the callout number, the
925 start and current positions in the text at the callout time, and the
926 next pattern item to be tested. For example:
927 --->pqrabcdef
929 0 ^ ^ \d
930 This output indicates that callout number 0 occurred for a match
932 attempt starting at the fourth character of the subject string, when
933 the pointer was at the seventh character of the data, and when the next
934 pattern item was \d. Just one circumflex is output if the start and
935 current positions are the same.
936 Callouts numbered 255 are assumed to be automatic callouts, inserted as
938 a result of the /C pattern modifier. In this case, instead of showing
939 the callout number, the offset in the pattern, preceded by a plus, is
940 output. For example:
941 re> /\d?[A-E]\*/C
943 data> E*
944 --->E*
945 +0 ^ \d?
946 +3 ^ [A-E]
947 +8 ^^ \*
948 +10 ^ ^
949 0: E*
950 If a pattern contains (*MARK) items, an additional line is output when‐
952 ever a change of latest mark is passed to the callout function. For
953 example:
954 re> /a(*MARK:X)bc/C
956 data> abc
957 --->abc
958 +0 ^ a
959 +1 ^^ (*MARK:X)
960 +10 ^^ b
961 Latest Mark: X
962 +11 ^ ^ c
963 +12 ^ ^
964 0: abc
965 The mark changes between matching "a" and "b", but stays the same for
967 the rest of the match, so nothing more is output. If, as a result of
968 backtracking, the mark reverts to being unset, the text "<unset>" is
969 output.
970 The callout function in pcretest returns zero (carry on matching) by
972 default, but you can use a \C item in a data line (as described above)
973 to change this and other parameters of the callout.
974 Inserting callouts can be helpful when using pcretest to check compli‐
976 cated regular expressions. For further information about callouts, see
977 the pcrecallout documentation.
978
980 When pcretest is outputting text in the compiled version of a pattern,
982 bytes other than 32-126 are always treated as non-printing characters
983 are are therefore shown as hex escapes.
984 When pcretest is outputting text that is a matched part of a subject
986 string, it behaves in the same way, unless a different locale has been
987 set for the pattern (using the /L modifier). In this case, the
988 isprint() function to distinguish printing and non-printing characters.
989
991 The facilities described in this section are not available when the
993 POSIX interface to PCRE is being used, that is, when the /P pattern
994 modifier is specified.
995 When the POSIX interface is not in use, you can cause pcretest to write
997 a compiled pattern to a file, by following the modifiers with > and a
998 file name. For example:
999 /pattern/im >/some/file
1001 See the pcreprecompile documentation for a discussion about saving and
1003 re-using compiled patterns. Note that if the pattern was successfully
1004 studied with JIT optimization, the JIT data cannot be saved.
1005 The data that is written is binary. The first eight bytes are the
1007 length of the compiled pattern data followed by the length of the
1008 optional study data, each written as four bytes in big-endian order
1009 (most significant byte first). If there is no study data (either the
1010 pattern was not studied, or studying did not return any data), the sec‐
1011 ond length is zero. The lengths are followed by an exact copy of the
1012 compiled pattern. If there is additional study data, this (excluding
1013 any JIT data) follows immediately after the compiled pattern. After
1014 writing the file, pcretest expects to read a new pattern.
1015 A saved pattern can be reloaded into pcretest by specifying < and a
1017 file name instead of a pattern. There must be no space between < and
1018 the file name, which must not contain a < character, as otherwise
1019 pcretest will interpret the line as a pattern delimited by < charac‐
1020 ters. For example:
1021 re> </some/file
1023 Compiled pattern loaded from /some/file
1024 No study data
1025 If the pattern was previously studied with the JIT optimization, the
1027 JIT information cannot be saved and restored, and so is lost. When the
1028 pattern has been loaded, pcretest proceeds to read data lines in the
1029 usual way.
1030 You can copy a file written by pcretest to a different host and reload
1032 it there, even if the new host has opposite endianness to the one on
1033 which the pattern was compiled. For example, you can compile on an i86
1034 machine and run on a SPARC machine. When a pattern is reloaded on a
1035 host with different endianness, the confirmation message is changed to:
1036 Compiled pattern (byte-inverted) loaded from /some/file
1038 The test suite contains some saved pre-compiled patterns with different
1040 endianness. These are reloaded using "<!" instead of just "<". This
1041 suppresses the "(byte-inverted)" text so that the output is the same on
1042 all hosts. It also forces debugging output once the pattern has been
1043 reloaded.
1044 File names for saving and reloading can be absolute or relative, but
1046 note that the shell facility of expanding a file name that starts with
1047 a tilde (~) is not available.
1048 The ability to save and reload files in pcretest is intended for test‐
1050 ing and experimentation. It is not intended for production use because
1051 only a single pattern can be written to a file. Furthermore, there is
1052 no facility for supplying custom character tables for use with a
1053 reloaded pattern. If the original pattern was compiled with custom
1054 tables, an attempt to match a subject string using a reloaded pattern
1055 is likely to cause pcretest to crash. Finally, if you attempt to load
1056 a file that is not in the correct format, the result is undefined.
1057
1059 pcre(3), pcre16(3), pcre32(3), pcreapi(3), pcrecallout(3), pcrejit,
1061 pcrematching(3), pcrepartial(d), pcrepattern(3), pcreprecompile(3).
1062
1064 Philip Hazel
1066 University Computing Service
1067 Cambridge CB2 3QH, England.
1068
1070 Last updated: 10 February 2020
1072 Copyright (c) 1997-2020 University of Cambridge.
1073PCRE 8.44 10 February 2020 PCRETEST(1)