1PCRETEST(1) PCRETEST(1) 2 3 4NAME 5 pcretest - a program for testing Perl-compatible regular expressions. 6 7 8SYNOPSIS 9 10 pcretest [options] [source] [destination] 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 documentation. 18 19 20OPTIONS 21 22 -b Behave as if each regex has the /B (show bytecode) modifier; 23 the internal form is output after compilation. 24 25 -C Output the version number of the PCRE library, and all avail- 26 able information about the optional features that are 27 included, and then exit. 28 29 -d Behave as if each regex has the /D (debug) modifier; the 30 internal form and information about the compiled pattern is 31 output after compilation; -d is equivalent to -b -i. 32 33 -dfa Behave as if each data line contains the \D escape sequence; 34 this causes the alternative matching function, 35 pcre_dfa_exec(), to be used instead of the standard 36 pcre_exec() function (more detail is given below). 37 38 -help Output a brief summary these options and then exit. 39 40 -i Behave as if each regex has the /I modifier; information 41 about the compiled pattern is given after compilation. 42 43 -M Behave as if each data line contains the \M escape sequence; 44 this causes PCRE to discover the minimum MATCH_LIMIT and 45 MATCH_LIMIT_RECURSION settings by calling pcre_exec() repeat- 46 edly with different limits. 47 48 -m Output the size of each compiled pattern after it has been 49 compiled. This is equivalent to adding /M to each regular 50 expression. For compatibility with earlier versions of 51 pcretest, -s is a synonym for -m. 52 53 -o osize Set the number of elements in the output vector that is used 54 when calling pcre_exec() or pcre_dfa_exec() to be osize. The 55 default value is 45, which is enough for 14 capturing subex- 56 pressions for pcre_exec() or 22 different matches for 57 pcre_dfa_exec(). The vector size can be changed for individ- 58 ual matching calls by including \O in the data line (see 59 below). 60 61 -p Behave as if each regex has the /P modifier; the POSIX wrap- 62 per API is used to call PCRE. None of the other options has 63 any effect when -p is set. 64 65 -q Do not output the version number of pcretest at the start of 66 execution. 67 68 -S size On Unix-like systems, set the size of the runtime stack to 69 size megabytes. 70 71 -t Run each compile, study, and match many times with a timer, 72 and output resulting time per compile or match (in millisec- 73 onds). Do not set -m with -t, because you will then get the 74 size output a zillion times, and the timing will be dis- 75 torted. You can control the number of iterations that are 76 used for timing by following -t with a number (as a separate 77 item on the command line). For example, "-t 1000" would iter- 78 ate 1000 times. The default is to iterate 500000 times. 79 80 -tm This is like -t except that it times only the matching phase, 81 not the compile or study phases. 82 83 84DESCRIPTION 85 86 If pcretest is given two filename arguments, it reads from the first 87 and writes to the second. If it is given only one filename argument, it 88 reads from that file and writes to stdout. Otherwise, it reads from 89 stdin and writes to stdout, and prompts for each line of input, using 90 "re>" to prompt for regular expressions, and "data>" to prompt for data 91 lines. 92 93 When pcretest is built, a configuration option can specify that it 94 should be linked with the libreadline library. When this is done, if 95 the input is from a terminal, it is read using the readline() function. 96 This provides line-editing and history facilities. The output from the 97 -help option states whether or not readline() will be used. 98 99 The program handles any number of sets of input on a single input file. 100 Each set starts with a regular expression, and continues with any num- 101 ber of data lines to be matched against the pattern. 102 103 Each data line is matched separately and independently. If you want to 104 do multi-line matches, you have to use the \n escape sequence (or \r or 105 \r\n, etc., depending on the newline setting) in a single line of input 106 to encode the newline sequences. There is no limit on the length of 107 data lines; the input buffer is automatically extended if it is too 108 small. 109 110 An empty line signals the end of the data lines, at which point a new 111 regular expression is read. The regular expressions are given enclosed 112 in any non-alphanumeric delimiters other than backslash, for example: 113 114 /(a|bc)x+yz/ 115 116 White space before the initial delimiter is ignored. A regular expres- 117 sion may be continued over several input lines, in which case the new- 118 line characters are included within it. It is possible to include the 119 delimiter within the pattern by escaping it, for example 120 121 /abc\/def/ 122 123 If you do so, the escape and the delimiter form part of the pattern, 124 but since delimiters are always non-alphanumeric, this does not affect 125 its interpretation. If the terminating delimiter is immediately fol- 126 lowed by a backslash, for example, 127 128 /abc/\ 129 130 then a backslash is added to the end of the pattern. This is done to 131 provide a way of testing the error condition that arises if a pattern 132 finishes with a backslash, because 133 134 /abc\/ 135 136 is interpreted as the first line of a pattern that starts with "abc/", 137 causing pcretest to read the next line as a continuation of the regular 138 expression. 139 140 141PATTERN MODIFIERS 142 143 A pattern may be followed by any number of modifiers, which are mostly 144 single characters. Following Perl usage, these are referred to below 145 as, for example, "the /i modifier", even though the delimiter of the 146 pattern need not always be a slash, and no slash is used when writing 147 modifiers. Whitespace may appear between the final pattern delimiter 148 and the first modifier, and between the modifiers themselves. 149 150 The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE, 151 PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when pcre_com- 152 pile() is called. These four modifier letters have the same effect as 153 they do in Perl. For example: 154 155 /caseless/i 156 157 The following table shows additional modifiers for setting PCRE com- 158 pile-time options that do not correspond to anything in Perl: 159 160 /8 PCRE_UTF8 161 /? PCRE_NO_UTF8_CHECK 162 /A PCRE_ANCHORED 163 /C PCRE_AUTO_CALLOUT 164 /E PCRE_DOLLAR_ENDONLY 165 /f PCRE_FIRSTLINE 166 /J PCRE_DUPNAMES 167 /N PCRE_NO_AUTO_CAPTURE 168 /U PCRE_UNGREEDY 169 /W PCRE_UCP 170 /X PCRE_EXTRA 171 /Y PCRE_NO_START_OPTIMIZE 172 /<JS> PCRE_JAVASCRIPT_COMPAT 173 /<cr> PCRE_NEWLINE_CR 174 /<lf> PCRE_NEWLINE_LF 175 /<crlf> PCRE_NEWLINE_CRLF 176 /<anycrlf> PCRE_NEWLINE_ANYCRLF 177 /<any> PCRE_NEWLINE_ANY 178 /<bsr_anycrlf> PCRE_BSR_ANYCRLF 179 /<bsr_unicode> PCRE_BSR_UNICODE 180 181 The modifiers that are enclosed in angle brackets are literal strings 182 as shown, including the angle brackets, but the letters can be in 183 either case. This example sets multiline matching with CRLF as the line 184 ending sequence: 185 186 /^abc/m<crlf> 187 188 As well as turning on the PCRE_UTF8 option, the /8 modifier also causes 189 any non-printing characters in output strings to be printed using the 190 \x{hh...} notation if they are valid UTF-8 sequences. Full details of 191 the PCRE options are given in the pcreapi documentation. 192 193 Finding all matches in a string 194 195 Searching for all possible matches within each subject string can be 196 requested by the /g or /G modifier. After finding a match, PCRE is 197 called again to search the remainder of the subject string. The differ- 198 ence between /g and /G is that the former uses the startoffset argument 199 to pcre_exec() to start searching at a new point within the entire 200 string (which is in effect what Perl does), whereas the latter passes 201 over a shortened substring. This makes a difference to the matching 202 process if the pattern begins with a lookbehind assertion (including \b 203 or \B). 204 205 If any call to pcre_exec() in a /g or /G sequence matches an empty 206 string, the next call is done with the PCRE_NOTEMPTY_ATSTART and 207 PCRE_ANCHORED flags set in order to search for another, non-empty, 208 match at the same point. If this second match fails, the start offset 209 is advanced, and the normal match is retried. This imitates the way 210 Perl handles such cases when using the /g modifier or the split() func- 211 tion. Normally, the start offset is advanced by one character, but if 212 the newline convention recognizes CRLF as a newline, and the current 213 character is CR followed by LF, an advance of two is used. 214 215 Other modifiers 216 217 There are yet more modifiers for controlling the way pcretest operates. 218 219 The /+ modifier requests that as well as outputting the substring that 220 matched the entire pattern, pcretest should in addition output the 221 remainder of the subject string. This is useful for tests where the 222 subject contains multiple copies of the same substring. 223 224 The /B modifier is a debugging feature. It requests that pcretest out- 225 put a representation of the compiled byte code after compilation. Nor- 226 mally this information contains length and offset values; however, if 227 /Z is also present, this data is replaced by spaces. This is a special 228 feature for use in the automatic test scripts; it ensures that the same 229 output is generated for different internal link sizes. 230 231 The /D modifier is a PCRE debugging feature, and is equivalent to /BI, 232 that is, both the /B and the /I modifiers. 233 234 The /F modifier causes pcretest to flip the byte order of the fields in 235 the compiled pattern that contain 2-byte and 4-byte numbers. This 236 facility is for testing the feature in PCRE that allows it to execute 237 patterns that were compiled on a host with a different endianness. This 238 feature is not available when the POSIX interface to PCRE is being 239 used, that is, when the /P pattern modifier is specified. See also the 240 section about saving and reloading compiled patterns below. 241 242 The /I modifier requests that pcretest output information about the 243 compiled pattern (whether it is anchored, has a fixed first character, 244 and so on). It does this by calling pcre_fullinfo() after compiling a 245 pattern. If the pattern is studied, the results of that are also out- 246 put. 247 248 The /K modifier requests pcretest to show names from backtracking con- 249 trol verbs that are returned from calls to pcre_exec(). It causes 250 pcretest to create a pcre_extra block if one has not already been cre- 251 ated by a call to pcre_study(), and to set the PCRE_EXTRA_MARK flag and 252 the mark field within it, every time that pcre_exec() is called. If the 253 variable that the mark field points to is non-NULL for a match, non- 254 match, or partial match, pcretest prints the string to which it points. 255 For a match, this is shown on a line by itself, tagged with "MK:". For 256 a non-match it is added to the message. 257 258 The /L modifier must be followed directly by the name of a locale, for 259 example, 260 261 /pattern/Lfr_FR 262 263 For this reason, it must be the last modifier. The given locale is set, 264 pcre_maketables() is called to build a set of character tables for the 265 locale, and this is then passed to pcre_compile() when compiling the 266 regular expression. Without an /L (or /T) modifier, NULL is passed as 267 the tables pointer; that is, /L applies only to the expression on which 268 it appears. 269 270 The /M modifier causes the size of memory block used to hold the com- 271 piled pattern to be output. 272 273 The /S modifier causes pcre_study() to be called after the expression 274 has been compiled, and the results used when the expression is matched. 275 276 The /T modifier must be followed by a single digit. It causes a spe- 277 cific set of built-in character tables to be passed to pcre_compile(). 278 It is used in the standard PCRE tests to check behaviour with different 279 character tables. The digit specifies the tables as follows: 280 281 0 the default ASCII tables, as distributed in 282 pcre_chartables.c.dist 283 1 a set of tables defining ISO 8859 characters 284 285 In table 1, some characters whose codes are greater than 128 are iden- 286 tified as letters, digits, spaces, etc. 287 288 Using the POSIX wrapper API 289 290 The /P modifier causes pcretest to call PCRE via the POSIX wrapper API 291 rather than its native API. When /P is set, the following modifiers set 292 options for the regcomp() function: 293 294 /i REG_ICASE 295 /m REG_NEWLINE 296 /N REG_NOSUB 297 /s REG_DOTALL ) 298 /U REG_UNGREEDY ) These options are not part of 299 /W REG_UCP ) the POSIX standard 300 /8 REG_UTF8 ) 301 302 The /+ modifier works as described above. All other modifiers are 303 ignored. 304 305 306DATA LINES 307 308 Before each data line is passed to pcre_exec(), leading and trailing 309 whitespace is removed, and it is then scanned for \ escapes. Some of 310 these are pretty esoteric features, intended for checking out some of 311 the more complicated features of PCRE. If you are just testing "ordi- 312 nary" regular expressions, you probably don't need any of these. The 313 following escapes are recognized: 314 315 \a alarm (BEL, \x07) 316 \b backspace (\x08) 317 \e escape (\x27) 318 \f formfeed (\x0c) 319 \n newline (\x0a) 320 \qdd set the PCRE_MATCH_LIMIT limit to dd 321 (any number of digits) 322 \r carriage return (\x0d) 323 \t tab (\x09) 324 \v vertical tab (\x0b) 325 \nnn octal character (up to 3 octal digits) 326 always a byte unless > 255 in UTF-8 mode 327 \xhh hexadecimal byte (up to 2 hex digits) 328 \x{hh...} hexadecimal character, any number of digits 329 in UTF-8 mode 330 \A pass the PCRE_ANCHORED option to pcre_exec() 331 or pcre_dfa_exec() 332 \B pass the PCRE_NOTBOL option to pcre_exec() 333 or pcre_dfa_exec() 334 \Cdd call pcre_copy_substring() for substring dd 335 after a successful match (number less than 32) 336 \Cname call pcre_copy_named_substring() for substring 337 "name" after a successful match (name termin- 338 ated by next non alphanumeric character) 339 \C+ show the current captured substrings at callout 340 time 341 \C- do not supply a callout function 342 \C!n return 1 instead of 0 when callout number n is 343 reached 344 \C!n!m return 1 instead of 0 when callout number n is 345 reached for the nth time 346 \C*n pass the number n (may be negative) as callout 347 data; this is used as the callout return value 348 \D use the pcre_dfa_exec() match function 349 \F only shortest match for pcre_dfa_exec() 350 \Gdd call pcre_get_substring() for substring dd 351 after a successful match (number less than 32) 352 \Gname call pcre_get_named_substring() for substring 353 "name" after a successful match (name termin- 354 ated by next non-alphanumeric character) 355 \L call pcre_get_substringlist() after a 356 successful match 357 \M discover the minimum MATCH_LIMIT and 358 MATCH_LIMIT_RECURSION settings 359 \N pass the PCRE_NOTEMPTY option to pcre_exec() 360 or pcre_dfa_exec(); if used twice, pass the 361 PCRE_NOTEMPTY_ATSTART option 362 \Odd set the size of the output vector passed to 363 pcre_exec() to dd (any number of digits) 364 \P pass the PCRE_PARTIAL_SOFT option to pcre_exec() 365 or pcre_dfa_exec(); if used twice, pass the 366 PCRE_PARTIAL_HARD option 367 \Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd 368 (any number of digits) 369 \R pass the PCRE_DFA_RESTART option to pcre_dfa_exec() 370 \S output details of memory get/free calls during matching 371 \Y pass the PCRE_NO_START_OPTIMIZE option to pcre_exec() 372 or pcre_dfa_exec() 373 \Z pass the PCRE_NOTEOL option to pcre_exec() 374 or pcre_dfa_exec() 375 \? pass the PCRE_NO_UTF8_CHECK option to 376 pcre_exec() or pcre_dfa_exec() 377 \>dd start the match at offset dd (optional "-"; then 378 any number of digits); this sets the startoffset 379 argument for pcre_exec() or pcre_dfa_exec() 380 \<cr> pass the PCRE_NEWLINE_CR option to pcre_exec() 381 or pcre_dfa_exec() 382 \<lf> pass the PCRE_NEWLINE_LF option to pcre_exec() 383 or pcre_dfa_exec() 384 \<crlf> pass the PCRE_NEWLINE_CRLF option to pcre_exec() 385 or pcre_dfa_exec() 386 \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre_exec() 387 or pcre_dfa_exec() 388 \<any> pass the PCRE_NEWLINE_ANY option to pcre_exec() 389 or pcre_dfa_exec() 390 391 Note that \xhh always specifies one byte, even in UTF-8 mode; this 392 makes it possible to construct invalid UTF-8 sequences for testing pur- 393 poses. On the other hand, \x{hh} is interpreted as a UTF-8 character in 394 UTF-8 mode, generating more than one byte if the value is greater than 395 127. When not in UTF-8 mode, it generates one byte for values less than 396 256, and causes an error for greater values. 397 398 The escapes that specify line ending sequences are literal strings, 399 exactly as shown. No more than one newline setting should be present in 400 any data line. 401 402 A backslash followed by anything else just escapes the anything else. 403 If the very last character is a backslash, it is ignored. This gives a 404 way of passing an empty line as data, since a real empty line termi- 405 nates the data input. 406 407 If \M is present, pcretest calls pcre_exec() several times, with dif- 408 ferent values in the match_limit and match_limit_recursion fields of 409 the pcre_extra data structure, until it finds the minimum numbers for 410 each parameter that allow pcre_exec() to complete. The match_limit num- 411 ber is a measure of the amount of backtracking that takes place, and 412 checking it out can be instructive. For most simple matches, the number 413 is quite small, but for patterns with very large numbers of matching 414 possibilities, it can become large very quickly with increasing length 415 of subject string. The match_limit_recursion number is a measure of how 416 much stack (or, if PCRE is compiled with NO_RECURSE, how much heap) 417 memory is needed to complete the match attempt. 418 419 When \O is used, the value specified may be higher or lower than the 420 size set by the -O command line option (or defaulted to 45); \O applies 421 only to the call of pcre_exec() for the line in which it appears. 422 423 If the /P modifier was present on the pattern, causing the POSIX wrap- 424 per API to be used, the only option-setting sequences that have any 425 effect are \B, \N, and \Z, causing REG_NOTBOL, REG_NOTEMPTY, and 426 REG_NOTEOL, respectively, to be passed to regexec(). 427 428 The use of \x{hh...} to represent UTF-8 characters is not dependent on 429 the use of the /8 modifier on the pattern. It is recognized always. 430 There may be any number of hexadecimal digits inside the braces. The 431 result is from one to six bytes, encoded according to the original 432 UTF-8 rules of RFC 2279. This allows for values in the range 0 to 433 0x7FFFFFFF. Note that not all of those are valid Unicode code points, 434 or indeed valid UTF-8 characters according to the later rules in RFC 435 3629. 436 437 438THE ALTERNATIVE MATCHING FUNCTION 439 440 By default, pcretest uses the standard PCRE matching function, 441 pcre_exec() to match each data line. From release 6.0, PCRE supports an 442 alternative matching function, pcre_dfa_test(), which operates in a 443 different way, and has some restrictions. The differences between the 444 two functions are described in the pcrematching documentation. 445 446 If a data line contains the \D escape sequence, or if the command line 447 contains the -dfa option, the alternative matching function is called. 448 This function finds all possible matches at a given point. If, however, 449 the \F escape sequence is present in the data line, it stops after the 450 first match is found. This is always the shortest possible match. 451 452 453DEFAULT OUTPUT FROM PCRETEST 454 455 This section describes the output when the normal matching function, 456 pcre_exec(), is being used. 457 458 When a match succeeds, pcretest outputs the list of captured substrings 459 that pcre_exec() returns, starting with number 0 for the string that 460 matched the whole pattern. Otherwise, it outputs "No match" when the 461 return is PCRE_ERROR_NOMATCH, and "Partial match:" followed by the par- 462 tially matching substring when pcre_exec() returns PCRE_ERROR_PARTIAL. 463 (Note that this is the entire substring that was inspected during the 464 partial match; it may include characters before the actual match start 465 if a lookbehind assertion, \K, \b, or \B was involved.) For any other 466 returns, it outputs the PCRE negative error number. Here is an example 467 of an interactive pcretest run. 468 469 $ pcretest 470 PCRE version 7.0 30-Nov-2006 471 472 re> /^abc(\d+)/ 473 data> abc123 474 0: abc123 475 1: 123 476 data> xyz 477 No match 478 479 Note that unset capturing substrings that are not followed by one that 480 is set are not returned by pcre_exec(), and are not shown by pcretest. 481 In the following example, there are two capturing substrings, but when 482 the first data line is matched, the second, unset substring is not 483 shown. An "internal" unset substring is shown as "<unset>", as for the 484 second data line. 485 486 re> /(a)|(b)/ 487 data> a 488 0: a 489 1: a 490 data> b 491 0: b 492 1: <unset> 493 2: b 494 495 If the strings contain any non-printing characters, they are output as 496 \0x escapes, or as \x{...} escapes if the /8 modifier was present on 497 the pattern. See below for the definition of non-printing characters. 498 If the pattern has the /+ modifier, the output for substring 0 is fol- 499 lowed by the the rest of the subject string, identified by "0+" like 500 this: 501 502 re> /cat/+ 503 data> cataract 504 0: cat 505 0+ aract 506 507 If the pattern has the /g or /G modifier, the results of successive 508 matching attempts are output in sequence, like this: 509 510 re> /\Bi(\w\w)/g 511 data> Mississippi 512 0: iss 513 1: ss 514 0: iss 515 1: ss 516 0: ipp 517 1: pp 518 519 "No match" is output only if the first match attempt fails. 520 521 If any of the sequences \C, \G, or \L are present in a data line that 522 is successfully matched, the substrings extracted by the convenience 523 functions are output with C, G, or L after the string number instead of 524 a colon. This is in addition to the normal full list. The string length 525 (that is, the return from the extraction function) is given in paren- 526 theses after each string for \C and \G. 527 528 Note that whereas patterns can be continued over several lines (a plain 529 ">" prompt is used for continuations), data lines may not. However new- 530 lines can be included in data by means of the \n escape (or \r, \r\n, 531 etc., depending on the newline sequence setting). 532 533 534OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION 535 536 When the alternative matching function, pcre_dfa_exec(), is used (by 537 means of the \D escape sequence or the -dfa command line option), the 538 output consists of a list of all the matches that start at the first 539 point in the subject where there is at least one match. For example: 540 541 re> /(tang|tangerine|tan)/ 542 data> yellow tangerine\D 543 0: tangerine 544 1: tang 545 2: tan 546 547 (Using the normal matching function on this data finds only "tang".) 548 The longest matching string is always given first (and numbered zero). 549 After a PCRE_ERROR_PARTIAL return, the output is "Partial match:", fol- 550 lowed by the partially matching substring. (Note that this is the 551 entire substring that was inspected during the partial match; it may 552 include characters before the actual match start if a lookbehind asser- 553 tion, \K, \b, or \B was involved.) 554 555 If /g is present on the pattern, the search for further matches resumes 556 at the end of the longest match. For example: 557 558 re> /(tang|tangerine|tan)/g 559 data> yellow tangerine and tangy sultana\D 560 0: tangerine 561 1: tang 562 2: tan 563 0: tang 564 1: tan 565 0: tan 566 567 Since the matching function does not support substring capture, the 568 escape sequences that are concerned with captured substrings are not 569 relevant. 570 571 572RESTARTING AFTER A PARTIAL MATCH 573 574 When the alternative matching function has given the PCRE_ERROR_PARTIAL 575 return, indicating that the subject partially matched the pattern, you 576 can restart the match with additional subject data by means of the \R 577 escape sequence. For example: 578 579 re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/ 580 data> 23ja\P\D 581 Partial match: 23ja 582 data> n05\R\D 583 0: n05 584 585 For further information about partial matching, see the pcrepartial 586 documentation. 587 588 589CALLOUTS 590 591 If the pattern contains any callout requests, pcretest's callout func- 592 tion is called during matching. This works with both matching func- 593 tions. By default, the called function displays the callout number, the 594 start and current positions in the text at the callout time, and the 595 next pattern item to be tested. For example, the output 596 597 --->pqrabcdef 598 0 ^ ^ \d 599 600 indicates that callout number 0 occurred for a match attempt starting 601 at the fourth character of the subject string, when the pointer was at 602 the seventh character of the data, and when the next pattern item was 603 \d. Just one circumflex is output if the start and current positions 604 are the same. 605 606 Callouts numbered 255 are assumed to be automatic callouts, inserted as 607 a result of the /C pattern modifier. In this case, instead of showing 608 the callout number, the offset in the pattern, preceded by a plus, is 609 output. For example: 610 611 re> /\d?[A-E]\*/C 612 data> E* 613 --->E* 614 +0 ^ \d? 615 +3 ^ [A-E] 616 +8 ^^ \* 617 +10 ^ ^ 618 0: E* 619 620 The callout function in pcretest returns zero (carry on matching) by 621 default, but you can use a \C item in a data line (as described above) 622 to change this. 623 624 Inserting callouts can be helpful when using pcretest to check compli- 625 cated regular expressions. For further information about callouts, see 626 the pcrecallout documentation. 627 628 629NON-PRINTING CHARACTERS 630 631 When pcretest is outputting text in the compiled version of a pattern, 632 bytes other than 32-126 are always treated as non-printing characters 633 are are therefore shown as hex escapes. 634 635 When pcretest is outputting text that is a matched part of a subject 636 string, it behaves in the same way, unless a different locale has been 637 set for the pattern (using the /L modifier). In this case, the 638 isprint() function to distinguish printing and non-printing characters. 639 640 641SAVING AND RELOADING COMPILED PATTERNS 642 643 The facilities described in this section are not available when the 644 POSIX inteface to PCRE is being used, that is, when the /P pattern mod- 645 ifier is specified. 646 647 When the POSIX interface is not in use, you can cause pcretest to write 648 a compiled pattern to a file, by following the modifiers with > and a 649 file name. For example: 650 651 /pattern/im >/some/file 652 653 See the pcreprecompile documentation for a discussion about saving and 654 re-using compiled patterns. 655 656 The data that is written is binary. The first eight bytes are the 657 length of the compiled pattern data followed by the length of the 658 optional study data, each written as four bytes in big-endian order 659 (most significant byte first). If there is no study data (either the 660 pattern was not studied, or studying did not return any data), the sec- 661 ond length is zero. The lengths are followed by an exact copy of the 662 compiled pattern. If there is additional study data, this follows imme- 663 diately after the compiled pattern. After writing the file, pcretest 664 expects to read a new pattern. 665 666 A saved pattern can be reloaded into pcretest by specifing < and a file 667 name instead of a pattern. The name of the file must not contain a < 668 character, as otherwise pcretest will interpret the line as a pattern 669 delimited by < characters. For example: 670 671 re> </some/file 672 Compiled regex loaded from /some/file 673 No study data 674 675 When the pattern has been loaded, pcretest proceeds to read data lines 676 in the usual way. 677 678 You can copy a file written by pcretest to a different host and reload 679 it there, even if the new host has opposite endianness to the one on 680 which the pattern was compiled. For example, you can compile on an i86 681 machine and run on a SPARC machine. 682 683 File names for saving and reloading can be absolute or relative, but 684 note that the shell facility of expanding a file name that starts with 685 a tilde (~) is not available. 686 687 The ability to save and reload files in pcretest is intended for test- 688 ing and experimentation. It is not intended for production use because 689 only a single pattern can be written to a file. Furthermore, there is 690 no facility for supplying custom character tables for use with a 691 reloaded pattern. If the original pattern was compiled with custom 692 tables, an attempt to match a subject string using a reloaded pattern 693 is likely to cause pcretest to crash. Finally, if you attempt to load 694 a file that is not in the correct format, the result is undefined. 695 696 697SEE ALSO 698 699 pcre(3), pcreapi(3), pcrecallout(3), pcrematching(3), pcrepartial(d), 700 pcrepattern(3), pcreprecompile(3). 701 702 703AUTHOR 704 705 Philip Hazel 706 University Computing Service 707 Cambridge CB2 3QH, England. 708 709 710REVISION 711 712 Last updated: 21 November 2010 713 Copyright (c) 1997-2010 University of Cambridge. 714