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1 PCRETEST(1) General Commands Manual PCRETEST(1)
2
3
4
5 NAME
6 pcretest - a program for testing Perl-compatible regular expressions.
7
8 SYNOPSIS
9
10 pcretest [options] [input file [output file]]
11
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.
18
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.
23
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.
30
31
32 INPUT DATA FORMAT
33
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.
41
42
43 PCRE's 8-BIT, 16-BIT AND 32-BIT LIBRARIES
44
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.
55
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".
59
60
61 COMMAND LINE OPTIONS
62
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.
67
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.
73
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.
79
80 -b Behave as if each pattern has the /B (show byte code) modi-
81 fier; the internal form is output after compilation.
82
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.
87
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:
92
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:
100 CR, LF, CRLF, ANYCRLF, or ANY
101 exit code is always 0
102
103 The following options output 1 for true or 0 for false, and
104 set the exit code to the same value:
105
106 ebcdic compiled for an EBCDIC environment
107 jit just-in-time support is available
108 pcre16 the 16-bit library was built
109 pcre32 the 32-bit library was built
110 pcre8 the 8-bit library was built
111 ucp Unicode property support is available
112 utf UTF-8 and/or UTF-16 and/or UTF-32 support
113 is available
114
115 If an unknown option is given, an error message is output;
116 the exit code is 0.
117
118 -d Behave as if each pattern has the /D (debug) modifier; the
119 internal form and information about the compiled pattern is
120 output after compilation; -d is equivalent to -b -i.
121
122 -dfa Behave as if each data line contains the \D escape sequence;
123 this causes the alternative matching function,
124 pcre[16|32]_dfa_exec(), to be used instead of the standard
125 pcre[16|32]_exec() function (more detail is given below).
126
127 -help Output a brief summary these options and then exit.
128
129 -i Behave as if each pattern has the /I modifier; information
130 about the compiled pattern is given after compilation.
131
132 -M Behave as if each data line contains the \M escape sequence;
133 this causes PCRE to discover the minimum MATCH_LIMIT and
134 MATCH_LIMIT_RECURSION settings by calling pcre[16|32]_exec()
135 repeatedly with different limits.
136
137 -m Output the size of each compiled pattern after it has been
138 compiled. This is equivalent to adding /M to each regular
139 expression. The size is given in bytes for both libraries.
140
141 -O Behave as if each pattern has the /O modifier, that is dis-
142 able auto-possessification for all patterns.
143
144 -o osize Set the number of elements in the output vector that is used
145 when calling pcre[16|32]_exec() or pcre[16|32]_dfa_exec() to
146 be osize. The default value is 45, which is enough for 14
147 capturing subexpressions for pcre[16|32]_exec() or 22 differ-
148 ent matches for pcre[16|32]_dfa_exec(). The vector size can
149 be changed for individual matching calls by including \O in
150 the data line (see below).
151
152 -p Behave as if each pattern has the /P modifier; the POSIX
153 wrapper API is used to call PCRE. None of the other options
154 has any effect when -p is set. This option can be used only
155 with the 8-bit library.
156
157 -q Do not output the version number of pcretest at the start of
158 execution.
159
160 -S size On Unix-like systems, set the size of the run-time stack to
161 size megabytes.
162
163 -s or -s+ Behave as if each pattern has the /S modifier; in other
164 words, force each pattern to be studied. If -s+ is used, all
165 the JIT compile options are passed to pcre[16|32]_study(),
166 causing just-in-time optimization to be set up if it is
167 available, for both full and partial matching. Specific JIT
168 compile options can be selected by following -s+ with a digit
169 in the range 1 to 7, which selects the JIT compile modes as
170 follows:
171
172 1 normal match only
173 2 soft partial match only
174 3 normal match and soft partial match
175 4 hard partial match only
176 6 soft and hard partial match
177 7 all three modes (default)
178
179 If -s++ is used instead of -s+ (with or without a following
180 digit), the text "(JIT)" is added to the first output line
181 after a match or no match when JIT-compiled code was actually
182 used.
183
184 Note that there are pattern options that can override -s,
185 either specifying no studying at all, or suppressing JIT com-
186 pilation.
187
188 If the /I or /D option is present on a pattern (requesting
189 output about the compiled pattern), information about the
190 result of studying is not included when studying is caused
191 only by -s and neither -i nor -d is present on the command
192 line. This behaviour means that the output from tests that
193 are run with and without -s should be identical, except when
194 options that output information about the actual running of a
195 match are set.
196
197 The -M, -t, and -tm options, which give information about
198 resources used, are likely to produce different output with
199 and without -s. Output may also differ if the /C option is
200 present on an individual pattern. This uses callouts to trace
201 the the matching process, and this may be different between
202 studied and non-studied patterns. If the pattern contains
203 (*MARK) items there may also be differences, for the same
204 reason. The -s command line option can be overridden for spe-
205 cific patterns that should never be studied (see the /S pat-
206 tern modifier below).
207
208 -t Run each compile, study, and match many times with a timer,
209 and output the resulting times per compile, study, or match
210 (in milliseconds). Do not set -m with -t, because you will
211 then get the size output a zillion times, and the timing will
212 be distorted. You can control the number of iterations that
213 are used for timing by following -t with a number (as a sepa-
214 rate item on the command line). For example, "-t 1000" iter-
215 ates 1000 times. The default is to iterate 500000 times.
216
217 -tm This is like -t except that it times only the matching phase,
218 not the compile or study phases.
219
220 -T -TM These behave like -t and -tm, but in addition, at the end of
221 a run, the total times for all compiles, studies, and matches
222 are output.
223
224
225 DESCRIPTION
226
227 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
234 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
240 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
244 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
251 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
255 /(a|bc)x+yz/
256
257 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
262 /abc\/def/
263
264 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
269 /abc/\
270
271 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
275 /abc\/
276
277 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
281
282 PATTERN MODIFIERS
283
284 A pattern may be followed by any number of modifiers, which are mostly
285 single characters, though some of these can be qualified by further
286 characters. Following Perl usage, these are referred to below as, for
287 example, "the /i modifier", even though the delimiter of the pattern
288 need not always be a slash, and no slash is used when writing modi-
289 fiers. White space may appear between the final pattern delimiter and
290 the first modifier, and between the modifiers themselves. For refer-
291 ence, here is a complete list of modifiers. They fall into several
292 groups that are described in detail in the following sections.
293
294 /8 set UTF mode
295 /9 set PCRE_NEVER_UTF (locks out UTF mode)
296 /? disable UTF validity check
297 /+ show remainder of subject after match
298 /= show all captures (not just those that are set)
299
300 /A set PCRE_ANCHORED
301 /B show compiled code
302 /C set PCRE_AUTO_CALLOUT
303 /D same as /B plus /I
304 /E set PCRE_DOLLAR_ENDONLY
305 /F flip byte order in compiled pattern
306 /f set PCRE_FIRSTLINE
307 /G find all matches (shorten string)
308 /g find all matches (use startoffset)
309 /I show information about pattern
310 /i set PCRE_CASELESS
311 /J set PCRE_DUPNAMES
312 /K show backtracking control names
313 /L set locale
314 /M show compiled memory size
315 /m set PCRE_MULTILINE
316 /N set PCRE_NO_AUTO_CAPTURE
317 /O set PCRE_NO_AUTO_POSSESS
318 /P use the POSIX wrapper
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
329 /<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
338
339 Perl-compatible modifiers
340
341 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
346 /caseless/i
347
348
349 Modifiers for other PCRE options
350
351 The following table shows additional modifiers for setting PCRE com-
352 pile-time options that do not correspond to anything in Perl:
353
354 /8 PCRE_UTF8 ) when using the 8-bit
355 /? PCRE_NO_UTF8_CHECK ) library
356
357 /8 PCRE_UTF16 ) when using the 16-bit
358 /? PCRE_NO_UTF16_CHECK ) library
359
360 /8 PCRE_UTF32 ) when using the 32-bit
361 /? PCRE_NO_UTF32_CHECK ) library
362
363 /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
384 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
389 /^abc/m<CRLF>
390
391 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
396 Full details of the PCRE options are given in the pcreapi documenta-
397 tion.
398
399 Finding all matches in a string
400
401 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
411 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
421 Other modifiers
422
423 There are yet more modifiers for controlling the way pcretest operates.
424
425 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
435 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
443 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
450 The /D modifier is a PCRE debugging feature, and is equivalent to /BI,
451 that is, both the /B and the /I modifiers.
452
453 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
461 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.
466
467 The /K modifier requests pcretest to show names from backtracking con-
468 trol verbs that are returned from calls to pcre[16|32]_exec(). It
469 causes pcretest to create a pcre[16|32]_extra block if one has not
470 already been created by a call to pcre[16|32]_study(), and to set the
471 PCRE_EXTRA_MARK flag and the mark field within it, every time that
472 pcre[16|32]_exec() is called. If the variable that the mark field
473 points to is non-NULL for a match, non-match, or partial match,
474 pcretest prints the string to which it points. For a match, this is
475 shown on a line by itself, tagged with "MK:". For a non-match it is
476 added to the message.
477
478 The /L modifier must be followed directly by the name of a locale, for
479 example,
480
481 /pattern/Lfr_FR
482
483 For this reason, it must be the last modifier. The given locale is set,
484 pcre[16|32]_maketables() is called to build a set of character tables
485 for the locale, and this is then passed to pcre[16|32]_compile() when
486 compiling the regular expression. Without an /L (or /T) modifier, NULL
487 is passed as the tables pointer; that is, /L applies only to the
488 expression on which it appears.
489
490 The /M modifier causes the size in bytes of the memory block used to
491 hold the compiled pattern to be output. This does not include the size
492 of the pcre[16|32] block; it is just the actual compiled data. If the
493 pattern is successfully studied with the PCRE_STUDY_JIT_COMPILE option,
494 the size of the JIT compiled code is also output.
495
496 The /S modifier causes pcre[16|32]_study() to be called after the
497 expression has been compiled, and the results used when the expression
498 is matched. There are a number of qualifying characters that may follow
499 /S. They may appear in any order.
500
501 If /S is followed by an exclamation mark, pcre[16|32]_study() is called
502 with the PCRE_STUDY_EXTRA_NEEDED option, causing it always to return a
503 pcre_extra block, even when studying discovers no useful information.
504
505 If /S is followed by a second S character, it suppresses studying, even
506 if it was requested externally by the -s command line option. This
507 makes it possible to specify that certain patterns are always studied,
508 and others are never studied, independently of -s. This feature is used
509 in the test files in a few cases where the output is different when the
510 pattern is studied.
511
512 If the /S modifier is followed by a + character, the call to
513 pcre[16|32]_study() is made with all the JIT study options, requesting
514 just-in-time optimization support if it is available, for both normal
515 and partial matching. If you want to restrict the JIT compiling modes,
516 you can follow /S+ with a digit in the range 1 to 7:
517
518 1 normal match only
519 2 soft partial match only
520 3 normal match and soft partial match
521 4 hard partial match only
522 6 soft and hard partial match
523 7 all three modes (default)
524
525 If /S++ is used instead of /S+ (with or without a following digit), the
526 text "(JIT)" is added to the first output line after a match or no
527 match when JIT-compiled code was actually used.
528
529 Note that there is also an independent /+ modifier; it must not be
530 given immediately after /S or /S+ because this will be misinterpreted.
531
532 If JIT studying is successful, the compiled JIT code will automatically
533 be used when pcre[16|32]_exec() is run, except when incompatible run-
534 time options are specified. For more details, see the pcrejit documen-
535 tation. See also the \J escape sequence below for a way of setting the
536 size of the JIT stack.
537
538 Finally, if /S is followed by a minus character, JIT compilation is
539 suppressed, even if it was requested externally by the -s command line
540 option. This makes it possible to specify that JIT is never to be used
541 for certain patterns.
542
543 The /T modifier must be followed by a single digit. It causes a spe-
544 cific set of built-in character tables to be passed to pcre[16|32]_com-
545 pile(). It is used in the standard PCRE tests to check behaviour with
546 different character tables. The digit specifies the tables as follows:
547
548 0 the default ASCII tables, as distributed in
549 pcre_chartables.c.dist
550 1 a set of tables defining ISO 8859 characters
551
552 In table 1, some characters whose codes are greater than 128 are iden-
553 tified as letters, digits, spaces, etc.
554
555 Using the POSIX wrapper API
556
557 The /P modifier causes pcretest to call PCRE via the POSIX wrapper API
558 rather than its native API. This supports only the 8-bit library. When
559 /P is set, the following modifiers set options for the regcomp() func-
560 tion:
561
562 /i REG_ICASE
563 /m REG_NEWLINE
564 /N REG_NOSUB
565 /s REG_DOTALL )
566 /U REG_UNGREEDY ) These options are not part of
567 /W REG_UCP ) the POSIX standard
568 /8 REG_UTF8 )
569
570 The /+ modifier works as described above. All other modifiers are
571 ignored.
572
573 Locking out certain modifiers
574
575 PCRE can be compiled with or without support for certain features such
576 as UTF-8/16/32 or Unicode properties. Accordingly, the standard tests
577 are split up into a number of different files that are selected for
578 running depending on which features are available. When updating the
579 tests, it is all too easy to put a new test into the wrong file by mis-
580 take; for example, to put a test that requires UTF support into a file
581 that is used when it is not available. To help detect such mistakes as
582 early as possible, there is a facility for locking out specific modi-
583 fiers. If an input line for pcretest starts with the string "< forbid "
584 the following sequence of characters is taken as a list of forbidden
585 modifiers. For example, in the test files that must not use UTF or Uni-
586 code property support, this line appears:
587
588 < forbid 8W
589
590 This locks out the /8 and /W modifiers. An immediate error is given if
591 they are subsequently encountered. If the character string contains <
592 but not >, all the multi-character modifiers that begin with < are
593 locked out. Otherwise, such modifiers must be explicitly listed, for
594 example:
595
596 < forbid <JS><cr>
597
598 There must be a single space between < and "forbid" for this feature to
599 be recognised. If there is not, the line is interpreted either as a
600 request to re-load a pre-compiled pattern (see "SAVING AND RELOADING
601 COMPILED PATTERNS" below) or, if there is a another < character, as a
602 pattern that uses < as its delimiter.
603
604
605 DATA LINES
606
607 Before each data line is passed to pcre[16|32]_exec(), leading and
608 trailing white space is removed, and it is then scanned for \ escapes.
609 Some of these are pretty esoteric features, intended for checking out
610 some of the more complicated features of PCRE. If you are just testing
611 "ordinary" regular expressions, you probably don't need any of these.
612 The following escapes are recognized:
613
614 \a alarm (BEL, \x07)
615 \b backspace (\x08)
616 \e escape (\x27)
617 \f form feed (\x0c)
618 \n newline (\x0a)
619 \qdd set the PCRE_MATCH_LIMIT limit to dd
620 (any number of digits)
621 \r carriage return (\x0d)
622 \t tab (\x09)
623 \v vertical tab (\x0b)
624 \nnn octal character (up to 3 octal digits); always
625 a byte unless > 255 in UTF-8 or 16-bit or 32-bit mode
626 \o{dd...} octal character (any number of octal digits}
627 \xhh hexadecimal byte (up to 2 hex digits)
628 \x{hh...} hexadecimal character (any number of hex digits)
629 \A pass the PCRE_ANCHORED option to pcre[16|32]_exec()
630 or pcre[16|32]_dfa_exec()
631 \B pass the PCRE_NOTBOL option to pcre[16|32]_exec()
632 or pcre[16|32]_dfa_exec()
633 \Cdd call pcre[16|32]_copy_substring() for substring dd
634 after a successful match (number less than 32)
635 \Cname call pcre[16|32]_copy_named_substring() for substring
636 "name" after a successful match (name termin-
637 ated by next non alphanumeric character)
638 \C+ show the current captured substrings at callout
639 time
640 \C- do not supply a callout function
641 \C!n return 1 instead of 0 when callout number n is
642 reached
643 \C!n!m return 1 instead of 0 when callout number n is
644 reached for the nth time
645 \C*n pass the number n (may be negative) as callout
646 data; this is used as the callout return value
647 \D use the pcre[16|32]_dfa_exec() match function
648 \F only shortest match for pcre[16|32]_dfa_exec()
649 \Gdd call pcre[16|32]_get_substring() for substring dd
650 after a successful match (number less than 32)
651 \Gname call pcre[16|32]_get_named_substring() for substring
652 "name" after a successful match (name termin-
653 ated by next non-alphanumeric character)
654 \Jdd set up a JIT stack of dd kilobytes maximum (any
655 number of digits)
656 \L call pcre[16|32]_get_substringlist() after a
657 successful match
658 \M discover the minimum MATCH_LIMIT and
659 MATCH_LIMIT_RECURSION settings
660 \N pass the PCRE_NOTEMPTY option to pcre[16|32]_exec()
661 or pcre[16|32]_dfa_exec(); if used twice, pass the
662 PCRE_NOTEMPTY_ATSTART option
663 \Odd set the size of the output vector passed to
664 pcre[16|32]_exec() to dd (any number of digits)
665 \P pass the PCRE_PARTIAL_SOFT option to pcre[16|32]_exec()
666 or pcre[16|32]_dfa_exec(); if used twice, pass the
667 PCRE_PARTIAL_HARD option
668 \Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd
669 (any number of digits)
670 \R pass the PCRE_DFA_RESTART option to pcre[16|32]_dfa_exec()
671 \S output details of memory get/free calls during matching
672 \Y pass the PCRE_NO_START_OPTIMIZE option to
673 pcre[16|32]_exec()
674 or pcre[16|32]_dfa_exec()
675 \Z pass the PCRE_NOTEOL option to pcre[16|32]_exec()
676 or pcre[16|32]_dfa_exec()
677 \? pass the PCRE_NO_UTF[8|16|32]_CHECK option to
678 pcre[16|32]_exec() or pcre[16|32]_dfa_exec()
679 \>dd start the match at offset dd (optional "-"; then
680 any number of digits); this sets the startoffset
681 argument for pcre[16|32]_exec() or
682 pcre[16|32]_dfa_exec()
683 \<cr> pass the PCRE_NEWLINE_CR option to pcre[16|32]_exec()
684 or pcre[16|32]_dfa_exec()
685 \<lf> pass the PCRE_NEWLINE_LF option to pcre[16|32]_exec()
686 or pcre[16|32]_dfa_exec()
687 \<crlf> pass the PCRE_NEWLINE_CRLF option to pcre[16|32]_exec()
688 or pcre[16|32]_dfa_exec()
689 \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre[16|32]_exec()
690 or pcre[16|32]_dfa_exec()
691 \<any> pass the PCRE_NEWLINE_ANY option to pcre[16|32]_exec()
692 or pcre[16|32]_dfa_exec()
693
694 The use of \x{hh...} is not dependent on the use of the /8 modifier on
695 the pattern. It is recognized always. There may be any number of hexa-
696 decimal digits inside the braces; invalid values provoke error mes-
697 sages.
698
699 Note that \xhh specifies one byte rather than one character in UTF-8
700 mode; this makes it possible to construct invalid UTF-8 sequences for
701 testing purposes. On the other hand, \x{hh} is interpreted as a UTF-8
702 character in UTF-8 mode, generating more than one byte if the value is
703 greater than 127. When testing the 8-bit library not in UTF-8 mode,
704 \x{hh} generates one byte for values less than 256, and causes an error
705 for greater values.
706
707 In UTF-16 mode, all 4-digit \x{hhhh} values are accepted. This makes it
708 possible to construct invalid UTF-16 sequences for testing purposes.
709
710 In UTF-32 mode, all 4- to 8-digit \x{...} values are accepted. This
711 makes it possible to construct invalid UTF-32 sequences for testing
712 purposes.
713
714 The escapes that specify line ending sequences are literal strings,
715 exactly as shown. No more than one newline setting should be present in
716 any data line.
717
718 A backslash followed by anything else just escapes the anything else.
719 If the very last character is a backslash, it is ignored. This gives a
720 way of passing an empty line as data, since a real empty line termi-
721 nates the data input.
722
723 The \J escape provides a way of setting the maximum stack size that is
724 used by the just-in-time optimization code. It is ignored if JIT opti-
725 mization is not being used. Providing a stack that is larger than the
726 default 32K is necessary only for very complicated patterns.
727
728 If \M is present, pcretest calls pcre[16|32]_exec() several times, with
729 different values in the match_limit and match_limit_recursion fields of
730 the pcre[16|32]_extra data structure, until it finds the minimum num-
731 bers for each parameter that allow pcre[16|32]_exec() to complete with-
732 out error. Because this is testing a specific feature of the normal
733 interpretive pcre[16|32]_exec() execution, the use of any JIT optimiza-
734 tion that might have been set up by the /S+ qualifier of -s+ option is
735 disabled.
736
737 The match_limit number is a measure of the amount of backtracking that
738 takes place, and checking it out can be instructive. For most simple
739 matches, the number is quite small, but for patterns with very large
740 numbers of matching possibilities, it can become large very quickly
741 with increasing length of subject string. The match_limit_recursion
742 number is a measure of how much stack (or, if PCRE is compiled with
743 NO_RECURSE, how much heap) memory is needed to complete the match
744 attempt.
745
746 When \O is used, the value specified may be higher or lower than the
747 size set by the -O command line option (or defaulted to 45); \O applies
748 only to the call of pcre[16|32]_exec() for the line in which it
749 appears.
750
751 If the /P modifier was present on the pattern, causing the POSIX wrap-
752 per API to be used, the only option-setting sequences that have any
753 effect are \B, \N, and \Z, causing REG_NOTBOL, REG_NOTEMPTY, and
754 REG_NOTEOL, respectively, to be passed to regexec().
755
756
757 THE ALTERNATIVE MATCHING FUNCTION
758
759 By default, pcretest uses the standard PCRE matching function,
760 pcre[16|32]_exec() to match each data line. PCRE also supports an
761 alternative matching function, pcre[16|32]_dfa_test(), which operates
762 in a different way, and has some restrictions. The differences between
763 the two functions are described in the pcrematching documentation.
764
765 If a data line contains the \D escape sequence, or if the command line
766 contains the -dfa option, the alternative matching function is used.
767 This function finds all possible matches at a given point. If, however,
768 the \F escape sequence is present in the data line, it stops after the
769 first match is found. This is always the shortest possible match.
770
771
772 DEFAULT OUTPUT FROM PCRETEST
773
774 This section describes the output when the normal matching function,
775 pcre[16|32]_exec(), is being used.
776
777 When a match succeeds, pcretest outputs the list of captured substrings
778 that pcre[16|32]_exec() returns, starting with number 0 for the string
779 that matched the whole pattern. Otherwise, it outputs "No match" when
780 the return is PCRE_ERROR_NOMATCH, and "Partial match:" followed by the
781 partially matching substring when pcre[16|32]_exec() returns
782 PCRE_ERROR_PARTIAL. (Note that this is the entire substring that was
783 inspected during the partial match; it may include characters before
784 the actual match start if a lookbehind assertion, \K, \b, or \B was
785 involved.) For any other return, pcretest outputs the PCRE negative
786 error number and a short descriptive phrase. If the error is a failed
787 UTF string check, the offset of the start of the failing character and
788 the reason code are also output, provided that the size of the output
789 vector is at least two. Here is an example of an interactive pcretest
790 run.
791
792 $ pcretest
793 PCRE version 8.13 2011-04-30
794
795 re> /^abc(\d+)/
796 data> abc123
797 0: abc123
798 1: 123
799 data> xyz
800 No match
801
802 Unset capturing substrings that are not followed by one that is set are
803 not returned by pcre[16|32]_exec(), and are not shown by pcretest. In
804 the following example, there are two capturing substrings, but when the
805 first data line is matched, the second, unset substring is not shown.
806 An "internal" unset substring is shown as "<unset>", as for the second
807 data line.
808
809 re> /(a)|(b)/
810 data> a
811 0: a
812 1: a
813 data> b
814 0: b
815 1: <unset>
816 2: b
817
818 If the strings contain any non-printing characters, they are output as
819 \xhh escapes if the value is less than 256 and UTF mode is not set.
820 Otherwise they are output as \x{hh...} escapes. See below for the defi-
821 nition of non-printing characters. If the pattern has the /+ modifier,
822 the output for substring 0 is followed by the the rest of the subject
823 string, identified by "0+" like this:
824
825 re> /cat/+
826 data> cataract
827 0: cat
828 0+ aract
829
830 If the pattern has the /g or /G modifier, the results of successive
831 matching attempts are output in sequence, like this:
832
833 re> /\Bi(\w\w)/g
834 data> Mississippi
835 0: iss
836 1: ss
837 0: iss
838 1: ss
839 0: ipp
840 1: pp
841
842 "No match" is output only if the first match attempt fails. Here is an
843 example of a failure message (the offset 4 that is specified by \>4 is
844 past the end of the subject string):
845
846 re> /xyz/
847 data> xyz\>4
848 Error -24 (bad offset value)
849
850 If any of the sequences \C, \G, or \L are present in a data line that
851 is successfully matched, the substrings extracted by the convenience
852 functions are output with C, G, or L after the string number instead of
853 a colon. This is in addition to the normal full list. The string length
854 (that is, the return from the extraction function) is given in paren-
855 theses after each string for \C and \G.
856
857 Note that whereas patterns can be continued over several lines (a plain
858 ">" prompt is used for continuations), data lines may not. However new-
859 lines can be included in data by means of the \n escape (or \r, \r\n,
860 etc., depending on the newline sequence setting).
861
862
863 OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
864
865 When the alternative matching function, pcre[16|32]_dfa_exec(), is used
866 (by means of the \D escape sequence or the -dfa command line option),
867 the output consists of a list of all the matches that start at the
868 first point in the subject where there is at least one match. For exam-
869 ple:
870
871 re> /(tang|tangerine|tan)/
872 data> yellow tangerine\D
873 0: tangerine
874 1: tang
875 2: tan
876
877 (Using the normal matching function on this data finds only "tang".)
878 The longest matching string is always given first (and numbered zero).
879 After a PCRE_ERROR_PARTIAL return, the output is "Partial match:", fol-
880 lowed by the partially matching substring. (Note that this is the
881 entire substring that was inspected during the partial match; it may
882 include characters before the actual match start if a lookbehind asser-
883 tion, \K, \b, or \B was involved.)
884
885 If /g is present on the pattern, the search for further matches resumes
886 at the end of the longest match. For example:
887
888 re> /(tang|tangerine|tan)/g
889 data> yellow tangerine and tangy sultana\D
890 0: tangerine
891 1: tang
892 2: tan
893 0: tang
894 1: tan
895 0: tan
896
897 Since the matching function does not support substring capture, the
898 escape sequences that are concerned with captured substrings are not
899 relevant.
900
901
902 RESTARTING AFTER A PARTIAL MATCH
903
904 When the alternative matching function has given the PCRE_ERROR_PARTIAL
905 return, indicating that the subject partially matched the pattern, you
906 can restart the match with additional subject data by means of the \R
907 escape sequence. For example:
908
909 re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
910 data> 23ja\P\D
911 Partial match: 23ja
912 data> n05\R\D
913 0: n05
914
915 For further information about partial matching, see the pcrepartial
916 documentation.
917
918
919 CALLOUTS
920
921 If the pattern contains any callout requests, pcretest's callout func-
922 tion is called during matching. This works with both matching func-
923 tions. By default, the called function displays the callout number, the
924 start and current positions in the text at the callout time, and the
925 next pattern item to be tested. For example:
926
927 --->pqrabcdef
928 0 ^ ^ \d
929
930 This output indicates that callout number 0 occurred for a match
931 attempt starting at the fourth character of the subject string, when
932 the pointer was at the seventh character of the data, and when the next
933 pattern item was \d. Just one circumflex is output if the start and
934 current positions are the same.
935
936 Callouts numbered 255 are assumed to be automatic callouts, inserted as
937 a result of the /C pattern modifier. In this case, instead of showing
938 the callout number, the offset in the pattern, preceded by a plus, is
939 output. For example:
940
941 re> /\d?[A-E]\*/C
942 data> E*
943 --->E*
944 +0 ^ \d?
945 +3 ^ [A-E]
946 +8 ^^ \*
947 +10 ^ ^
948 0: E*
949
950 If a pattern contains (*MARK) items, an additional line is output when-
951 ever a change of latest mark is passed to the callout function. For
952 example:
953
954 re> /a(*MARK:X)bc/C
955 data> abc
956 --->abc
957 +0 ^ a
958 +1 ^^ (*MARK:X)
959 +10 ^^ b
960 Latest Mark: X
961 +11 ^ ^ c
962 +12 ^ ^
963 0: abc
964
965 The mark changes between matching "a" and "b", but stays the same for
966 the rest of the match, so nothing more is output. If, as a result of
967 backtracking, the mark reverts to being unset, the text "<unset>" is
968 output.
969
970 The callout function in pcretest returns zero (carry on matching) by
971 default, but you can use a \C item in a data line (as described above)
972 to change this and other parameters of the callout.
973
974 Inserting callouts can be helpful when using pcretest to check compli-
975 cated regular expressions. For further information about callouts, see
976 the pcrecallout documentation.
977
978
979 NON-PRINTING CHARACTERS
980
981 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
985 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
990
991 SAVING AND RELOADING COMPILED PATTERNS
992
993 The facilities described in this section are not available when the
994 POSIX interface to PCRE is being used, that is, when the /P pattern
995 modifier is specified.
996
997 When the POSIX interface is not in use, you can cause pcretest to write
998 a compiled pattern to a file, by following the modifiers with > and a
999 file name. For example:
1000
1001 /pattern/im >/some/file
1002
1003 See the pcreprecompile documentation for a discussion about saving and
1004 re-using compiled patterns. Note that if the pattern was successfully
1005 studied with JIT optimization, the JIT data cannot be saved.
1006
1007 The data that is written is binary. The first eight bytes are the
1008 length of the compiled pattern data followed by the length of the
1009 optional study data, each written as four bytes in big-endian order
1010 (most significant byte first). If there is no study data (either the
1011 pattern was not studied, or studying did not return any data), the sec-
1012 ond length is zero. The lengths are followed by an exact copy of the
1013 compiled pattern. If there is additional study data, this (excluding
1014 any JIT data) follows immediately after the compiled pattern. After
1015 writing the file, pcretest expects to read a new pattern.
1016
1017 A saved pattern can be reloaded into pcretest by specifying < and a
1018 file name instead of a pattern. There must be no space between < and
1019 the file name, which must not contain a < character, as otherwise
1020 pcretest will interpret the line as a pattern delimited by < charac-
1021 ters. For example:
1022
1023 re> </some/file
1024 Compiled pattern loaded from /some/file
1025 No study data
1026
1027 If the pattern was previously studied with the JIT optimization, the
1028 JIT information cannot be saved and restored, and so is lost. When the
1029 pattern has been loaded, pcretest proceeds to read data lines in the
1030 usual way.
1031
1032 You can copy a file written by pcretest to a different host and reload
1033 it there, even if the new host has opposite endianness to the one on
1034 which the pattern was compiled. For example, you can compile on an i86
1035 machine and run on a SPARC machine. When a pattern is reloaded on a
1036 host with different endianness, the confirmation message is changed to:
1037
1038 Compiled pattern (byte-inverted) loaded from /some/file
1039
1040 The test suite contains some saved pre-compiled patterns with different
1041 endianness. These are reloaded using "<!" instead of just "<". This
1042 suppresses the "(byte-inverted)" text so that the output is the same on
1043 all hosts. It also forces debugging output once the pattern has been
1044 reloaded.
1045
1046 File names for saving and reloading can be absolute or relative, but
1047 note that the shell facility of expanding a file name that starts with
1048 a tilde (~) is not available.
1049
1050 The ability to save and reload files in pcretest is intended for test-
1051 ing and experimentation. It is not intended for production use because
1052 only a single pattern can be written to a file. Furthermore, there is
1053 no facility for supplying custom character tables for use with a
1054 reloaded pattern. If the original pattern was compiled with custom
1055 tables, an attempt to match a subject string using a reloaded pattern
1056 is likely to cause pcretest to crash. Finally, if you attempt to load
1057 a file that is not in the correct format, the result is undefined.
1058
1059
1060 SEE ALSO
1061
1062 pcre(3), pcre16(3), pcre32(3), pcreapi(3), pcrecallout(3), pcrejit,
1063 pcrematching(3), pcrepartial(d), pcrepattern(3), pcreprecompile(3).
1064
1065
1066 AUTHOR
1067
1068 Philip Hazel
1069 University Computing Service
1070 Cambridge CB2 3QH, England.
1071
1072
1073 REVISION
1074
1075 Last updated: 12 November 2013
1076 Copyright (c) 1997-2013 University of Cambridge.

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