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1 <html>
2 <head>
3 <title>pcretest specification</title>
4 </head>
5 <body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB">
6 This HTML document has been generated automatically from the original man page.
7 If there is any nonsense in it, please consult the man page, in case the
8 conversion went wrong.<br>
9 <ul>
10 <li><a name="TOC1" href="#SEC1">SYNOPSIS</a>
11 <li><a name="TOC2" href="#SEC2">OPTIONS</a>
12 <li><a name="TOC3" href="#SEC3">DESCRIPTION</a>
13 <li><a name="TOC4" href="#SEC4">PATTERN MODIFIERS</a>
14 <li><a name="TOC5" href="#SEC5">CALLOUTS</a>
15 <li><a name="TOC6" href="#SEC6">DATA LINES</a>
16 <li><a name="TOC7" href="#SEC7">OUTPUT FROM PCRETEST</a>
17 <li><a name="TOC8" href="#SEC8">AUTHOR</a>
18 </ul>
19 <br><a name="SEC1" href="#TOC1">SYNOPSIS</a><br>
20 <P>
21 <b>pcretest [-d] [-i] [-m] [-o osize] [-p] [-t] [source] [destination]</b>
22 </P>
23 <P>
24 <b>pcretest</b> was written as a test program for the PCRE regular expression
25 library itself, but it can also be used for experimenting with regular
26 expressions. This document describes the features of the test program; for
27 details of the regular expressions themselves, see the
28 <a href="pcrepattern.html"><b>pcrepattern</b></a>
29 documentation. For details of PCRE and its options, see the
30 <a href="pcreapi.html"><b>pcreapi</b></a>
31 documentation.
32 </P>
33 <br><a name="SEC2" href="#TOC1">OPTIONS</a><br>
34 <P>
35 <b>-C</b>
36 Output the version number of the PCRE library, and all available information
37 about the optional features that are included, and then exit.
38 </P>
39 <P>
40 <b>-d</b>
41 Behave as if each regex had the <b>/D</b> modifier (see below); the internal
42 form is output after compilation.
43 </P>
44 <P>
45 <b>-i</b>
46 Behave as if each regex had the <b>/I</b> modifier; information about the
47 compiled pattern is given after compilation.
48 </P>
49 <P>
50 <b>-m</b>
51 Output the size of each compiled pattern after it has been compiled. This is
52 equivalent to adding /M to each regular expression. For compatibility with
53 earlier versions of pcretest, <b>-s</b> is a synonym for <b>-m</b>.
54 </P>
55 <P>
56 <b>-o</b> <i>osize</i>
57 Set the number of elements in the output vector that is used when calling PCRE
58 to be <i>osize</i>. The default value is 45, which is enough for 14 capturing
59 subexpressions. The vector size can be changed for individual matching calls by
60 including \O in the data line (see below).
61 </P>
62 <P>
63 <b>-p</b>
64 Behave as if each regex has <b>/P</b> modifier; the POSIX wrapper API is used
65 to call PCRE. None of the other options has any effect when <b>-p</b> is set.
66 </P>
67 <P>
68 <b>-t</b>
69 Run each compile, study, and match many times with a timer, and output
70 resulting time per compile or match (in milliseconds). Do not set <b>-t</b> with
71 <b>-m</b>, because you will then get the size output 20000 times and the timing
72 will be distorted.
73 </P>
74 <br><a name="SEC3" href="#TOC1">DESCRIPTION</a><br>
75 <P>
76 If <b>pcretest</b> is given two filename arguments, it reads from the first and
77 writes to the second. If it is given only one filename argument, it reads from
78 that file and writes to stdout. Otherwise, it reads from stdin and writes to
79 stdout, and prompts for each line of input, using "re&#62;" to prompt for regular
80 expressions, and "data&#62;" to prompt for data lines.
81 </P>
82 <P>
83 The program handles any number of sets of input on a single input file. Each
84 set starts with a regular expression, and continues with any number of data
85 lines to be matched against the pattern.
86 </P>
87 <P>
88 Each line is matched separately and independently. If you want to do
89 multiple-line matches, you have to use the \n escape sequence in a single line
90 of input to encode the newline characters. The maximum length of data line is
91 30,000 characters.
92 </P>
93 <P>
94 An empty line signals the end of the data lines, at which point a new regular
95 expression is read. The regular expressions are given enclosed in any
96 non-alphameric delimiters other than backslash, for example
97 </P>
98 <P>
99 <pre>
100 /(a|bc)x+yz/
101 </PRE>
102 </P>
103 <P>
104 White space before the initial delimiter is ignored. A regular expression may
105 be continued over several input lines, in which case the newline characters are
106 included within it. It is possible to include the delimiter within the pattern
107 by escaping it, for example
108 </P>
109 <P>
110 <pre>
111 /abc\/def/
112 </PRE>
113 </P>
114 <P>
115 If you do so, the escape and the delimiter form part of the pattern, but since
116 delimiters are always non-alphameric, this does not affect its interpretation.
117 If the terminating delimiter is immediately followed by a backslash, for
118 example,
119 </P>
120 <P>
121 <pre>
122 /abc/\
123 </PRE>
124 </P>
125 <P>
126 then a backslash is added to the end of the pattern. This is done to provide a
127 way of testing the error condition that arises if a pattern finishes with a
128 backslash, because
129 </P>
130 <P>
131 <pre>
132 /abc\/
133 </PRE>
134 </P>
135 <P>
136 is interpreted as the first line of a pattern that starts with "abc/", causing
137 pcretest to read the next line as a continuation of the regular expression.
138 </P>
139 <br><a name="SEC4" href="#TOC1">PATTERN MODIFIERS</a><br>
140 <P>
141 The pattern may be followed by <b>i</b>, <b>m</b>, <b>s</b>, or <b>x</b> to set the
142 PCRE_CASELESS, PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options,
143 respectively. For example:
144 </P>
145 <P>
146 <pre>
147 /caseless/i
148 </PRE>
149 </P>
150 <P>
151 These modifier letters have the same effect as they do in Perl. There are
152 others that set PCRE options that do not correspond to anything in Perl:
153 <b>/A</b>, <b>/E</b>, <b>/N</b>, <b>/U</b>, and <b>/X</b> set PCRE_ANCHORED,
154 PCRE_DOLLAR_ENDONLY, PCRE_NO_AUTO_CAPTURE, PCRE_UNGREEDY, and PCRE_EXTRA
155 respectively.
156 </P>
157 <P>
158 Searching for all possible matches within each subject string can be requested
159 by the <b>/g</b> or <b>/G</b> modifier. After finding a match, PCRE is called
160 again to search the remainder of the subject string. The difference between
161 <b>/g</b> and <b>/G</b> is that the former uses the <i>startoffset</i> argument to
162 <b>pcre_exec()</b> to start searching at a new point within the entire string
163 (which is in effect what Perl does), whereas the latter passes over a shortened
164 substring. This makes a difference to the matching process if the pattern
165 begins with a lookbehind assertion (including \b or \B).
166 </P>
167 <P>
168 If any call to <b>pcre_exec()</b> in a <b>/g</b> or <b>/G</b> sequence matches an
169 empty string, the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED
170 flags set in order to search for another, non-empty, match at the same point.
171 If this second match fails, the start offset is advanced by one, and the normal
172 match is retried. This imitates the way Perl handles such cases when using the
173 <b>/g</b> modifier or the <b>split()</b> function.
174 </P>
175 <P>
176 There are a number of other modifiers for controlling the way <b>pcretest</b>
177 operates.
178 </P>
179 <P>
180 The <b>/+</b> modifier requests that as well as outputting the substring that
181 matched the entire pattern, pcretest should in addition output the remainder of
182 the subject string. This is useful for tests where the subject contains
183 multiple copies of the same substring.
184 </P>
185 <P>
186 The <b>/L</b> modifier must be followed directly by the name of a locale, for
187 example,
188 </P>
189 <P>
190 <pre>
191 /pattern/Lfr
192 </PRE>
193 </P>
194 <P>
195 For this reason, it must be the last modifier letter. The given locale is set,
196 <b>pcre_maketables()</b> is called to build a set of character tables for the
197 locale, and this is then passed to <b>pcre_compile()</b> when compiling the
198 regular expression. Without an <b>/L</b> modifier, NULL is passed as the tables
199 pointer; that is, <b>/L</b> applies only to the expression on which it appears.
200 </P>
201 <P>
202 The <b>/I</b> modifier requests that <b>pcretest</b> output information about the
203 compiled expression (whether it is anchored, has a fixed first character, and
204 so on). It does this by calling <b>pcre_fullinfo()</b> after compiling an
205 expression, and outputting the information it gets back. If the pattern is
206 studied, the results of that are also output.
207 </P>
208 <P>
209 The <b>/D</b> modifier is a PCRE debugging feature, which also assumes <b>/I</b>.
210 It causes the internal form of compiled regular expressions to be output after
211 compilation. If the pattern was studied, the information returned is also
212 output.
213 </P>
214 <P>
215 The <b>/S</b> modifier causes <b>pcre_study()</b> to be called after the
216 expression has been compiled, and the results used when the expression is
217 matched.
218 </P>
219 <P>
220 The <b>/M</b> modifier causes the size of memory block used to hold the compiled
221 pattern to be output.
222 </P>
223 <P>
224 The <b>/P</b> modifier causes <b>pcretest</b> to call PCRE via the POSIX wrapper
225 API rather than its native API. When this is done, all other modifiers except
226 <b>/i</b>, <b>/m</b>, and <b>/+</b> are ignored. REG_ICASE is set if <b>/i</b> is
227 present, and REG_NEWLINE is set if <b>/m</b> is present. The wrapper functions
228 force PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.
229 </P>
230 <P>
231 The <b>/8</b> modifier causes <b>pcretest</b> to call PCRE with the PCRE_UTF8
232 option set. This turns on support for UTF-8 character handling in PCRE,
233 provided that it was compiled with this support enabled. This modifier also
234 causes any non-printing characters in output strings to be printed using the
235 \x{hh...} notation if they are valid UTF-8 sequences.
236 </P>
237 <P>
238 If the <b>/?</b> modifier is used with <b>/8</b>, it causes <b>pcretest</b> to
239 call <b>pcre_compile()</b> with the PCRE_NO_UTF8_CHECK option, to suppress the
240 checking of the string for UTF-8 validity.
241 </P>
242 <br><a name="SEC5" href="#TOC1">CALLOUTS</a><br>
243 <P>
244 If the pattern contains any callout requests, <b>pcretest</b>'s callout function
245 will be called. By default, it displays the callout number, and the start and
246 current positions in the text at the callout time. For example, the output
247 </P>
248 <P>
249 <pre>
250 ---&#62;pqrabcdef
251 0 ^ ^
252 </PRE>
253 </P>
254 <P>
255 indicates that callout number 0 occurred for a match attempt starting at the
256 fourth character of the subject string, when the pointer was at the seventh
257 character. The callout function returns zero (carry on matching) by default.
258 </P>
259 <P>
260 Inserting callouts may be helpful when using <b>pcretest</b> to check
261 complicated regular expressions. For further information about callouts, see
262 the
263 <a href="pcrecallout.html"><b>pcrecallout</b></a>
264 documentation.
265 </P>
266 <P>
267 For testing the PCRE library, additional control of callout behaviour is
268 available via escape sequences in the data, as described in the following
269 section. In particular, it is possible to pass in a number as callout data (the
270 default is zero). If the callout function receives a non-zero number, it
271 returns that value instead of zero.
272 </P>
273 <br><a name="SEC6" href="#TOC1">DATA LINES</a><br>
274 <P>
275 Before each data line is passed to <b>pcre_exec()</b>, leading and trailing
276 whitespace is removed, and it is then scanned for \ escapes. Some of these are
277 pretty esoteric features, intended for checking out some of the more
278 complicated features of PCRE. If you are just testing "ordinary" regular
279 expressions, you probably don't need any of these. The following escapes are
280 recognized:
281 </P>
282 <P>
283 <pre>
284 \a alarm (= BEL)
285 \b backspace
286 \e escape
287 \f formfeed
288 \n newline
289 \r carriage return
290 \t tab
291 \v vertical tab
292 \nnn octal character (up to 3 octal digits)
293 \xhh hexadecimal character (up to 2 hex digits)
294 \x{hh...} hexadecimal character, any number of digits
295 in UTF-8 mode
296 \A pass the PCRE_ANCHORED option to <b>pcre_exec()</b>
297 \B pass the PCRE_NOTBOL option to <b>pcre_exec()</b>
298 \Cdd call pcre_copy_substring() for substring dd
299 after a successful match (any decimal number
300 less than 32)
301 \Cname call pcre_copy_named_substring() for substring
302 "name" after a successful match (name termin-
303 ated by next non alphanumeric character)
304 \C+ show the current captured substrings at callout
305 time
306 \C- do not supply a callout function
307 \C!n return 1 instead of 0 when callout number n is
308 reached
309 \C!n!m return 1 instead of 0 when callout number n is
310 reached for the nth time
311 \C*n pass the number n (may be negative) as callout
312 data
313 \Gdd call pcre_get_substring() for substring dd
314 after a successful match (any decimal number
315 less than 32)
316 \Gname call pcre_get_named_substring() for substring
317 "name" after a successful match (name termin-
318 ated by next non-alphanumeric character)
319 \L call pcre_get_substringlist() after a
320 successful match
321 \M discover the minimum MATCH_LIMIT setting
322 \N pass the PCRE_NOTEMPTY option to <b>pcre_exec()</b>
323 \Odd set the size of the output vector passed to
324 <b>pcre_exec()</b> to dd (any number of decimal
325 digits)
326 \Z pass the PCRE_NOTEOL option to <b>pcre_exec()</b>
327 \? pass the PCRE_NO_UTF8_CHECK option to
328 <b>pcre_exec()</b>
329 </PRE>
330 </P>
331 <P>
332 If \M is present, <b>pcretest</b> calls <b>pcre_exec()</b> several times, with
333 different values in the <i>match_limit</i> field of the <b>pcre_extra</b> data
334 structure, until it finds the minimum number that is needed for
335 <b>pcre_exec()</b> to complete. This number is a measure of the amount of
336 recursion and backtracking that takes place, and checking it out can be
337 instructive. For most simple matches, the number is quite small, but for
338 patterns with very large numbers of matching possibilities, it can become large
339 very quickly with increasing length of subject string.
340 </P>
341 <P>
342 When \O is used, it may be higher or lower than the size set by the <b>-O</b>
343 option (or defaulted to 45); \O applies only to the call of <b>pcre_exec()</b>
344 for the line in which it appears.
345 </P>
346 <P>
347 A backslash followed by anything else just escapes the anything else. If the
348 very last character is a backslash, it is ignored. This gives a way of passing
349 an empty line as data, since a real empty line terminates the data input.
350 </P>
351 <P>
352 If <b>/P</b> was present on the regex, causing the POSIX wrapper API to be used,
353 only <b>\B</b>, and <b>\Z</b> have any effect, causing REG_NOTBOL and REG_NOTEOL
354 to be passed to <b>regexec()</b> respectively.
355 </P>
356 <P>
357 The use of \x{hh...} to represent UTF-8 characters is not dependent on the use
358 of the <b>/8</b> modifier on the pattern. It is recognized always. There may be
359 any number of hexadecimal digits inside the braces. The result is from one to
360 six bytes, encoded according to the UTF-8 rules.
361 </P>
362 <br><a name="SEC7" href="#TOC1">OUTPUT FROM PCRETEST</a><br>
363 <P>
364 When a match succeeds, pcretest outputs the list of captured substrings that
365 <b>pcre_exec()</b> returns, starting with number 0 for the string that matched
366 the whole pattern. Here is an example of an interactive pcretest run.
367 </P>
368 <P>
369 <pre>
370 $ pcretest
371 PCRE version 4.00 08-Jan-2003
372 </PRE>
373 </P>
374 <P>
375 <pre>
376 re&#62; /^abc(\d+)/
377 data&#62; abc123
378 0: abc123
379 1: 123
380 data&#62; xyz
381 No match
382 </PRE>
383 </P>
384 <P>
385 If the strings contain any non-printing characters, they are output as \0x
386 escapes, or as \x{...} escapes if the <b>/8</b> modifier was present on the
387 pattern. If the pattern has the <b>/+</b> modifier, then the output for
388 substring 0 is followed by the the rest of the subject string, identified by
389 "0+" like this:
390 </P>
391 <P>
392 <pre>
393 re&#62; /cat/+
394 data&#62; cataract
395 0: cat
396 0+ aract
397 </PRE>
398 </P>
399 <P>
400 If the pattern has the <b>/g</b> or <b>/G</b> modifier, the results of successive
401 matching attempts are output in sequence, like this:
402 </P>
403 <P>
404 <pre>
405 re&#62; /\Bi(\w\w)/g
406 data&#62; Mississippi
407 0: iss
408 1: ss
409 0: iss
410 1: ss
411 0: ipp
412 1: pp
413 </PRE>
414 </P>
415 <P>
416 "No match" is output only if the first match attempt fails.
417 </P>
418 <P>
419 If any of the sequences <b>\C</b>, <b>\G</b>, or <b>\L</b> are present in a
420 data line that is successfully matched, the substrings extracted by the
421 convenience functions are output with C, G, or L after the string number
422 instead of a colon. This is in addition to the normal full list. The string
423 length (that is, the return from the extraction function) is given in
424 parentheses after each string for <b>\C</b> and <b>\G</b>.
425 </P>
426 <P>
427 Note that while patterns can be continued over several lines (a plain "&#62;"
428 prompt is used for continuations), data lines may not. However newlines can be
429 included in data by means of the \n escape.
430 </P>
431 <br><a name="SEC8" href="#TOC1">AUTHOR</a><br>
432 <P>
433 Philip Hazel &#60;ph10@cam.ac.uk&#62;
434 <br>
435 University Computing Service,
436 <br>
437 Cambridge CB2 3QG, England.
438 </P>
439 <P>
440 Last updated: 20 August 2003
441 <br>
442 Copyright &copy; 1997-2003 University of Cambridge.

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