1<html> 2<head> 3<title>pcretest specification</title> 4</head> 5<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> 6<h1>pcretest man page</h1> 7<p> 8Return to the <a href="index.html">PCRE index page</a>. 9</p> 10<p> 11This page is part of the PCRE HTML documentation. It was generated automatically 12from the original man page. If there is any nonsense in it, please consult the 13man page, in case the conversion went wrong. 14<br> 15<ul> 16<li><a name="TOC1" href="#SEC1">SYNOPSIS</a> 17<li><a name="TOC2" href="#SEC2">OPTIONS</a> 18<li><a name="TOC3" href="#SEC3">DESCRIPTION</a> 19<li><a name="TOC4" href="#SEC4">PATTERN MODIFIERS</a> 20<li><a name="TOC5" href="#SEC5">DATA LINES</a> 21<li><a name="TOC6" href="#SEC6">THE ALTERNATIVE MATCHING FUNCTION</a> 22<li><a name="TOC7" href="#SEC7">DEFAULT OUTPUT FROM PCRETEST</a> 23<li><a name="TOC8" href="#SEC8">OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION</a> 24<li><a name="TOC9" href="#SEC9">RESTARTING AFTER A PARTIAL MATCH</a> 25<li><a name="TOC10" href="#SEC10">CALLOUTS</a> 26<li><a name="TOC11" href="#SEC11">NON-PRINTING CHARACTERS</a> 27<li><a name="TOC12" href="#SEC12">SAVING AND RELOADING COMPILED PATTERNS</a> 28<li><a name="TOC13" href="#SEC13">SEE ALSO</a> 29<li><a name="TOC14" href="#SEC14">AUTHOR</a> 30<li><a name="TOC15" href="#SEC15">REVISION</a> 31</ul> 32<br><a name="SEC1" href="#TOC1">SYNOPSIS</a><br> 33<P> 34<b>pcretest [options] [source] [destination]</b> 35<br> 36<br> 37<b>pcretest</b> was written as a test program for the PCRE regular expression 38library itself, but it can also be used for experimenting with regular 39expressions. This document describes the features of the test program; for 40details of the regular expressions themselves, see the 41<a href="pcrepattern.html"><b>pcrepattern</b></a> 42documentation. For details of the PCRE library function calls and their 43options, see the 44<a href="pcreapi.html"><b>pcreapi</b></a> 45documentation. 46</P> 47<br><a name="SEC2" href="#TOC1">OPTIONS</a><br> 48<P> 49<b>-b</b> 50Behave as if each regex has the <b>/B</b> (show bytecode) modifier; the internal 51form is output after compilation. 52</P> 53<P> 54<b>-C</b> 55Output the version number of the PCRE library, and all available information 56about the optional features that are included, and then exit. 57</P> 58<P> 59<b>-d</b> 60Behave as if each regex has the <b>/D</b> (debug) modifier; the internal 61form and information about the compiled pattern is output after compilation; 62<b>-d</b> is equivalent to <b>-b -i</b>. 63</P> 64<P> 65<b>-dfa</b> 66Behave as if each data line contains the \D escape sequence; this causes the 67alternative matching function, <b>pcre_dfa_exec()</b>, to be used instead of the 68standard <b>pcre_exec()</b> function (more detail is given below). 69</P> 70<P> 71<b>-help</b> 72Output a brief summary these options and then exit. 73</P> 74<P> 75<b>-i</b> 76Behave as if each regex has the <b>/I</b> modifier; information about the 77compiled pattern is given after compilation. 78</P> 79<P> 80<b>-M</b> 81Behave as if each data line contains the \M escape sequence; this causes 82PCRE to discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings by 83calling <b>pcre_exec()</b> repeatedly with different limits. 84</P> 85<P> 86<b>-m</b> 87Output the size of each compiled pattern after it has been compiled. This is 88equivalent to adding <b>/M</b> to each regular expression. For compatibility 89with earlier versions of pcretest, <b>-s</b> is a synonym for <b>-m</b>. 90</P> 91<P> 92<b>-o</b> <i>osize</i> 93Set the number of elements in the output vector that is used when calling 94<b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> to be <i>osize</i>. The default value 95is 45, which is enough for 14 capturing subexpressions for <b>pcre_exec()</b> or 9622 different matches for <b>pcre_dfa_exec()</b>. The vector size can be 97changed for individual matching calls by including \O in the data line (see 98below). 99</P> 100<P> 101<b>-p</b> 102Behave as if each regex has the <b>/P</b> modifier; the POSIX wrapper API is 103used to call PCRE. None of the other options has any effect when <b>-p</b> is 104set. 105</P> 106<P> 107<b>-q</b> 108Do not output the version number of <b>pcretest</b> at the start of execution. 109</P> 110<P> 111<b>-S</b> <i>size</i> 112On Unix-like systems, set the size of the runtime stack to <i>size</i> 113megabytes. 114</P> 115<P> 116<b>-t</b> 117Run each compile, study, and match many times with a timer, and output 118resulting time per compile or match (in milliseconds). Do not set <b>-m</b> with 119<b>-t</b>, because you will then get the size output a zillion times, and the 120timing will be distorted. You can control the number of iterations that are 121used for timing by following <b>-t</b> with a number (as a separate item on the 122command line). For example, "-t 1000" would iterate 1000 times. The default is 123to iterate 500000 times. 124</P> 125<P> 126<b>-tm</b> 127This is like <b>-t</b> except that it times only the matching phase, not the 128compile or study phases. 129</P> 130<br><a name="SEC3" href="#TOC1">DESCRIPTION</a><br> 131<P> 132If <b>pcretest</b> is given two filename arguments, it reads from the first and 133writes to the second. If it is given only one filename argument, it reads from 134that file and writes to stdout. Otherwise, it reads from stdin and writes to 135stdout, and prompts for each line of input, using "re>" to prompt for regular 136expressions, and "data>" to prompt for data lines. 137</P> 138<P> 139When <b>pcretest</b> is built, a configuration option can specify that it should 140be linked with the <b>libreadline</b> library. When this is done, if the input 141is from a terminal, it is read using the <b>readline()</b> function. This 142provides line-editing and history facilities. The output from the <b>-help</b> 143option states whether or not <b>readline()</b> will be used. 144</P> 145<P> 146The program handles any number of sets of input on a single input file. Each 147set starts with a regular expression, and continues with any number of data 148lines to be matched against the pattern. 149</P> 150<P> 151Each data line is matched separately and independently. If you want to do 152multi-line matches, you have to use the \n escape sequence (or \r or \r\n, 153etc., depending on the newline setting) in a single line of input to encode the 154newline sequences. There is no limit on the length of data lines; the input 155buffer is automatically extended if it is too small. 156</P> 157<P> 158An empty line signals the end of the data lines, at which point a new regular 159expression is read. The regular expressions are given enclosed in any 160non-alphanumeric delimiters other than backslash, for example: 161<pre> 162 /(a|bc)x+yz/ 163</pre> 164White space before the initial delimiter is ignored. A regular expression may 165be continued over several input lines, in which case the newline characters are 166included within it. It is possible to include the delimiter within the pattern 167by escaping it, for example 168<pre> 169 /abc\/def/ 170</pre> 171If you do so, the escape and the delimiter form part of the pattern, but since 172delimiters are always non-alphanumeric, this does not affect its interpretation. 173If the terminating delimiter is immediately followed by a backslash, for 174example, 175<pre> 176 /abc/\ 177</pre> 178then a backslash is added to the end of the pattern. This is done to provide a 179way of testing the error condition that arises if a pattern finishes with a 180backslash, because 181<pre> 182 /abc\/ 183</pre> 184is interpreted as the first line of a pattern that starts with "abc/", causing 185pcretest to read the next line as a continuation of the regular expression. 186</P> 187<br><a name="SEC4" href="#TOC1">PATTERN MODIFIERS</a><br> 188<P> 189A pattern may be followed by any number of modifiers, which are mostly single 190characters. Following Perl usage, these are referred to below as, for example, 191"the <b>/i</b> modifier", even though the delimiter of the pattern need not 192always be a slash, and no slash is used when writing modifiers. Whitespace may 193appear between the final pattern delimiter and the first modifier, and between 194the modifiers themselves. 195</P> 196<P> 197The <b>/i</b>, <b>/m</b>, <b>/s</b>, and <b>/x</b> modifiers set the PCRE_CASELESS, 198PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when 199<b>pcre_compile()</b> is called. These four modifier letters have the same 200effect as they do in Perl. For example: 201<pre> 202 /caseless/i 203</pre> 204The following table shows additional modifiers for setting PCRE compile-time 205options that do not correspond to anything in Perl: 206<pre> 207 <b>/8</b> PCRE_UTF8 208 <b>/?</b> PCRE_NO_UTF8_CHECK 209 <b>/A</b> PCRE_ANCHORED 210 <b>/C</b> PCRE_AUTO_CALLOUT 211 <b>/E</b> PCRE_DOLLAR_ENDONLY 212 <b>/f</b> PCRE_FIRSTLINE 213 <b>/J</b> PCRE_DUPNAMES 214 <b>/N</b> PCRE_NO_AUTO_CAPTURE 215 <b>/U</b> PCRE_UNGREEDY 216 <b>/W</b> PCRE_UCP 217 <b>/X</b> PCRE_EXTRA 218 <b>/Y</b> PCRE_NO_START_OPTIMIZE 219 <b>/<JS></b> PCRE_JAVASCRIPT_COMPAT 220 <b>/<cr></b> PCRE_NEWLINE_CR 221 <b>/<lf></b> PCRE_NEWLINE_LF 222 <b>/<crlf></b> PCRE_NEWLINE_CRLF 223 <b>/<anycrlf></b> PCRE_NEWLINE_ANYCRLF 224 <b>/<any></b> PCRE_NEWLINE_ANY 225 <b>/<bsr_anycrlf></b> PCRE_BSR_ANYCRLF 226 <b>/<bsr_unicode></b> PCRE_BSR_UNICODE 227</pre> 228The modifiers that are enclosed in angle brackets are literal strings as shown, 229including the angle brackets, but the letters can be in either case. This 230example sets multiline matching with CRLF as the line ending sequence: 231<pre> 232 /^abc/m<crlf> 233</pre> 234As well as turning on the PCRE_UTF8 option, the <b>/8</b> modifier also causes 235any non-printing characters in output strings to be printed using the 236\x{hh...} notation if they are valid UTF-8 sequences. Full details of the PCRE 237options are given in the 238<a href="pcreapi.html"><b>pcreapi</b></a> 239documentation. 240</P> 241<br><b> 242Finding all matches in a string 243</b><br> 244<P> 245Searching for all possible matches within each subject string can be requested 246by the <b>/g</b> or <b>/G</b> modifier. After finding a match, PCRE is called 247again to search the remainder of the subject string. The difference between 248<b>/g</b> and <b>/G</b> is that the former uses the <i>startoffset</i> argument to 249<b>pcre_exec()</b> to start searching at a new point within the entire string 250(which is in effect what Perl does), whereas the latter passes over a shortened 251substring. This makes a difference to the matching process if the pattern 252begins with a lookbehind assertion (including \b or \B). 253</P> 254<P> 255If any call to <b>pcre_exec()</b> in a <b>/g</b> or <b>/G</b> sequence matches an 256empty string, the next call is done with the PCRE_NOTEMPTY_ATSTART and 257PCRE_ANCHORED flags set in order to search for another, non-empty, match at the 258same point. If this second match fails, the start offset is advanced, and the 259normal match is retried. This imitates the way Perl handles such cases when 260using the <b>/g</b> modifier or the <b>split()</b> function. Normally, the start 261offset is advanced by one character, but if the newline convention recognizes 262CRLF as a newline, and the current character is CR followed by LF, an advance 263of two is used. 264</P> 265<br><b> 266Other modifiers 267</b><br> 268<P> 269There are yet more modifiers for controlling the way <b>pcretest</b> 270operates. 271</P> 272<P> 273The <b>/+</b> modifier requests that as well as outputting the substring that 274matched the entire pattern, pcretest should in addition output the remainder of 275the subject string. This is useful for tests where the subject contains 276multiple copies of the same substring. 277</P> 278<P> 279The <b>/B</b> modifier is a debugging feature. It requests that <b>pcretest</b> 280output a representation of the compiled byte code after compilation. Normally 281this information contains length and offset values; however, if <b>/Z</b> is 282also present, this data is replaced by spaces. This is a special feature for 283use in the automatic test scripts; it ensures that the same output is generated 284for different internal link sizes. 285</P> 286<P> 287The <b>/D</b> modifier is a PCRE debugging feature, and is equivalent to 288<b>/BI</b>, that is, both the <b>/B</b> and the <b>/I</b> modifiers. 289</P> 290<P> 291The <b>/F</b> modifier causes <b>pcretest</b> to flip the byte order of the 292fields in the compiled pattern that contain 2-byte and 4-byte numbers. This 293facility is for testing the feature in PCRE that allows it to execute patterns 294that were compiled on a host with a different endianness. This feature is not 295available when the POSIX interface to PCRE is being used, that is, when the 296<b>/P</b> pattern modifier is specified. See also the section about saving and 297reloading compiled patterns below. 298</P> 299<P> 300The <b>/I</b> modifier requests that <b>pcretest</b> output information about the 301compiled pattern (whether it is anchored, has a fixed first character, and 302so on). It does this by calling <b>pcre_fullinfo()</b> after compiling a 303pattern. If the pattern is studied, the results of that are also output. 304</P> 305<P> 306The <b>/K</b> modifier requests <b>pcretest</b> to show names from backtracking 307control verbs that are returned from calls to <b>pcre_exec()</b>. It causes 308<b>pcretest</b> to create a <b>pcre_extra</b> block if one has not already been 309created by a call to <b>pcre_study()</b>, and to set the PCRE_EXTRA_MARK flag 310and the <b>mark</b> field within it, every time that <b>pcre_exec()</b> is 311called. If the variable that the <b>mark</b> field points to is non-NULL for a 312match, non-match, or partial match, <b>pcretest</b> prints the string to which 313it points. For a match, this is shown on a line by itself, tagged with "MK:". 314For a non-match it is added to the message. 315</P> 316<P> 317The <b>/L</b> modifier must be followed directly by the name of a locale, for 318example, 319<pre> 320 /pattern/Lfr_FR 321</pre> 322For this reason, it must be the last modifier. The given locale is set, 323<b>pcre_maketables()</b> is called to build a set of character tables for the 324locale, and this is then passed to <b>pcre_compile()</b> when compiling the 325regular expression. Without an <b>/L</b> (or <b>/T</b>) modifier, NULL is passed 326as the tables pointer; that is, <b>/L</b> applies only to the expression on 327which it appears. 328</P> 329<P> 330The <b>/M</b> modifier causes the size of memory block used to hold the compiled 331pattern to be output. 332</P> 333<P> 334The <b>/S</b> modifier causes <b>pcre_study()</b> to be called after the 335expression has been compiled, and the results used when the expression is 336matched. 337</P> 338<P> 339The <b>/T</b> modifier must be followed by a single digit. It causes a specific 340set of built-in character tables to be passed to <b>pcre_compile()</b>. It is 341used in the standard PCRE tests to check behaviour with different character 342tables. The digit specifies the tables as follows: 343<pre> 344 0 the default ASCII tables, as distributed in 345 pcre_chartables.c.dist 346 1 a set of tables defining ISO 8859 characters 347</pre> 348In table 1, some characters whose codes are greater than 128 are identified as 349letters, digits, spaces, etc. 350</P> 351<br><b> 352Using the POSIX wrapper API 353</b><br> 354<P> 355The <b>/P</b> modifier causes <b>pcretest</b> to call PCRE via the POSIX wrapper 356API rather than its native API. When <b>/P</b> is set, the following modifiers 357set options for the <b>regcomp()</b> function: 358<pre> 359 /i REG_ICASE 360 /m REG_NEWLINE 361 /N REG_NOSUB 362 /s REG_DOTALL ) 363 /U REG_UNGREEDY ) These options are not part of 364 /W REG_UCP ) the POSIX standard 365 /8 REG_UTF8 ) 366</pre> 367The <b>/+</b> modifier works as described above. All other modifiers are 368ignored. 369</P> 370<br><a name="SEC5" href="#TOC1">DATA LINES</a><br> 371<P> 372Before each data line is passed to <b>pcre_exec()</b>, leading and trailing 373whitespace is removed, and it is then scanned for \ escapes. Some of these are 374pretty esoteric features, intended for checking out some of the more 375complicated features of PCRE. If you are just testing "ordinary" regular 376expressions, you probably don't need any of these. The following escapes are 377recognized: 378<pre> 379 \a alarm (BEL, \x07) 380 \b backspace (\x08) 381 \e escape (\x27) 382 \f formfeed (\x0c) 383 \n newline (\x0a) 384 \qdd set the PCRE_MATCH_LIMIT limit to dd (any number of digits) 385 \r carriage return (\x0d) 386 \t tab (\x09) 387 \v vertical tab (\x0b) 388 \nnn octal character (up to 3 octal digits) 389 always a byte unless > 255 in UTF-8 mode 390 \xhh hexadecimal byte (up to 2 hex digits) 391 \x{hh...} hexadecimal character, any number of digits in UTF-8 mode 392 \A pass the PCRE_ANCHORED option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> 393 \B pass the PCRE_NOTBOL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> 394 \Cdd call pcre_copy_substring() for substring dd after a successful match (number less than 32) 395 \Cname call pcre_copy_named_substring() for substring "name" after a successful match (name termin- 396 ated by next non alphanumeric character) 397 \C+ show the current captured substrings at callout time 398 \C- do not supply a callout function 399 \C!n return 1 instead of 0 when callout number n is reached 400 \C!n!m return 1 instead of 0 when callout number n is reached for the nth time 401 \C*n pass the number n (may be negative) as callout data; this is used as the callout return value 402 \D use the <b>pcre_dfa_exec()</b> match function 403 \F only shortest match for <b>pcre_dfa_exec()</b> 404 \Gdd call pcre_get_substring() for substring dd after a successful match (number less than 32) 405 \Gname call pcre_get_named_substring() for substring "name" after a successful match (name termin- 406 ated by next non-alphanumeric character) 407 \L call pcre_get_substringlist() after a successful match 408 \M discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings 409 \N pass the PCRE_NOTEMPTY option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>; if used twice, pass the 410 PCRE_NOTEMPTY_ATSTART option 411 \Odd set the size of the output vector passed to <b>pcre_exec()</b> to dd (any number of digits) 412 \P pass the PCRE_PARTIAL_SOFT option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>; if used twice, pass the 413 PCRE_PARTIAL_HARD option 414 \Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd (any number of digits) 415 \R pass the PCRE_DFA_RESTART option to <b>pcre_dfa_exec()</b> 416 \S output details of memory get/free calls during matching 417 \Y pass the PCRE_NO_START_OPTIMIZE option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> 418 \Z pass the PCRE_NOTEOL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> 419 \? pass the PCRE_NO_UTF8_CHECK option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> 420 \>dd start the match at offset dd (optional "-"; then any number of digits); this sets the <i>startoffset</i> 421 argument for <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> 422 \<cr> pass the PCRE_NEWLINE_CR option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> 423 \<lf> pass the PCRE_NEWLINE_LF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> 424 \<crlf> pass the PCRE_NEWLINE_CRLF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> 425 \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> 426 \<any> pass the PCRE_NEWLINE_ANY option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> 427</pre> 428Note that \xhh always specifies one byte, even in UTF-8 mode; this makes it 429possible to construct invalid UTF-8 sequences for testing purposes. On the 430other hand, \x{hh} is interpreted as a UTF-8 character in UTF-8 mode, 431generating more than one byte if the value is greater than 127. When not in 432UTF-8 mode, it generates one byte for values less than 256, and causes an error 433for greater values. 434</P> 435<P> 436The escapes that specify line ending sequences are literal strings, exactly as 437shown. No more than one newline setting should be present in any data line. 438</P> 439<P> 440A backslash followed by anything else just escapes the anything else. If 441the very last character is a backslash, it is ignored. This gives a way of 442passing an empty line as data, since a real empty line terminates the data 443input. 444</P> 445<P> 446If \M is present, <b>pcretest</b> calls <b>pcre_exec()</b> several times, with 447different values in the <i>match_limit</i> and <i>match_limit_recursion</i> 448fields of the <b>pcre_extra</b> data structure, until it finds the minimum 449numbers for each parameter that allow <b>pcre_exec()</b> to complete. The 450<i>match_limit</i> number is a measure of the amount of backtracking that takes 451place, and checking it out can be instructive. For most simple matches, the 452number is quite small, but for patterns with very large numbers of matching 453possibilities, it can become large very quickly with increasing length of 454subject string. The <i>match_limit_recursion</i> number is a measure of how much 455stack (or, if PCRE is compiled with NO_RECURSE, how much heap) memory is needed 456to complete the match attempt. 457</P> 458<P> 459When \O is used, the value specified may be higher or lower than the size set 460by the <b>-O</b> command line option (or defaulted to 45); \O applies only to 461the call of <b>pcre_exec()</b> for the line in which it appears. 462</P> 463<P> 464If the <b>/P</b> modifier was present on the pattern, causing the POSIX wrapper 465API to be used, the only option-setting sequences that have any effect are \B, 466\N, and \Z, causing REG_NOTBOL, REG_NOTEMPTY, and REG_NOTEOL, respectively, 467to be passed to <b>regexec()</b>. 468</P> 469<P> 470The use of \x{hh...} to represent UTF-8 characters is not dependent on the use 471of the <b>/8</b> modifier on the pattern. It is recognized always. There may be 472any number of hexadecimal digits inside the braces. The result is from one to 473six bytes, encoded according to the original UTF-8 rules of RFC 2279. This 474allows for values in the range 0 to 0x7FFFFFFF. Note that not all of those are 475valid Unicode code points, or indeed valid UTF-8 characters according to the 476later rules in RFC 3629. 477</P> 478<br><a name="SEC6" href="#TOC1">THE ALTERNATIVE MATCHING FUNCTION</a><br> 479<P> 480By default, <b>pcretest</b> uses the standard PCRE matching function, 481<b>pcre_exec()</b> to match each data line. From release 6.0, PCRE supports an 482alternative matching function, <b>pcre_dfa_test()</b>, which operates in a 483different way, and has some restrictions. The differences between the two 484functions are described in the 485<a href="pcrematching.html"><b>pcrematching</b></a> 486documentation. 487</P> 488<P> 489If a data line contains the \D escape sequence, or if the command line 490contains the <b>-dfa</b> option, the alternative matching function is called. 491This function finds all possible matches at a given point. If, however, the \F 492escape sequence is present in the data line, it stops after the first match is 493found. This is always the shortest possible match. 494</P> 495<br><a name="SEC7" href="#TOC1">DEFAULT OUTPUT FROM PCRETEST</a><br> 496<P> 497This section describes the output when the normal matching function, 498<b>pcre_exec()</b>, is being used. 499</P> 500<P> 501When a match succeeds, pcretest outputs the list of captured substrings that 502<b>pcre_exec()</b> returns, starting with number 0 for the string that matched 503the whole pattern. Otherwise, it outputs "No match" when the return is 504PCRE_ERROR_NOMATCH, and "Partial match:" followed by the partially matching 505substring when <b>pcre_exec()</b> returns PCRE_ERROR_PARTIAL. (Note that this is 506the entire substring that was inspected during the partial match; it may 507include characters before the actual match start if a lookbehind assertion, 508\K, \b, or \B was involved.) For any other returns, it outputs the PCRE 509negative error number. Here is an example of an interactive <b>pcretest</b> run. 510<pre> 511 $ pcretest 512 PCRE version 7.0 30-Nov-2006 513 514 re> /^abc(\d+)/ 515 data> abc123 516 0: abc123 517 1: 123 518 data> xyz 519 No match 520</pre> 521Note that unset capturing substrings that are not followed by one that is set 522are not returned by <b>pcre_exec()</b>, and are not shown by <b>pcretest</b>. In 523the following example, there are two capturing substrings, but when the first 524data line is matched, the second, unset substring is not shown. An "internal" 525unset substring is shown as "<unset>", as for the second data line. 526<pre> 527 re> /(a)|(b)/ 528 data> a 529 0: a 530 1: a 531 data> b 532 0: b 533 1: <unset> 534 2: b 535</pre> 536If the strings contain any non-printing characters, they are output as \0x 537escapes, or as \x{...} escapes if the <b>/8</b> modifier was present on the 538pattern. See below for the definition of non-printing characters. If the 539pattern has the <b>/+</b> modifier, the output for substring 0 is followed by 540the the rest of the subject string, identified by "0+" like this: 541<pre> 542 re> /cat/+ 543 data> cataract 544 0: cat 545 0+ aract 546</pre> 547If the pattern has the <b>/g</b> or <b>/G</b> modifier, the results of successive 548matching attempts are output in sequence, like this: 549<pre> 550 re> /\Bi(\w\w)/g 551 data> Mississippi 552 0: iss 553 1: ss 554 0: iss 555 1: ss 556 0: ipp 557 1: pp 558</pre> 559"No match" is output only if the first match attempt fails. 560</P> 561<P> 562If any of the sequences <b>\C</b>, <b>\G</b>, or <b>\L</b> are present in a 563data line that is successfully matched, the substrings extracted by the 564convenience functions are output with C, G, or L after the string number 565instead of a colon. This is in addition to the normal full list. The string 566length (that is, the return from the extraction function) is given in 567parentheses after each string for <b>\C</b> and <b>\G</b>. 568</P> 569<P> 570Note that whereas patterns can be continued over several lines (a plain ">" 571prompt is used for continuations), data lines may not. However newlines can be 572included in data by means of the \n escape (or \r, \r\n, etc., depending on 573the newline sequence setting). 574</P> 575<br><a name="SEC8" href="#TOC1">OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION</a><br> 576<P> 577When the alternative matching function, <b>pcre_dfa_exec()</b>, is used (by 578means of the \D escape sequence or the <b>-dfa</b> command line option), the 579output consists of a list of all the matches that start at the first point in 580the subject where there is at least one match. For example: 581<pre> 582 re> /(tang|tangerine|tan)/ 583 data> yellow tangerine\D 584 0: tangerine 585 1: tang 586 2: tan 587</pre> 588(Using the normal matching function on this data finds only "tang".) The 589longest matching string is always given first (and numbered zero). After a 590PCRE_ERROR_PARTIAL return, the output is "Partial match:", followed by the 591partially matching substring. (Note that this is the entire substring that was 592inspected during the partial match; it may include characters before the actual 593match start if a lookbehind assertion, \K, \b, or \B was involved.) 594</P> 595<P> 596If <b>/g</b> is present on the pattern, the search for further matches resumes 597at the end of the longest match. For example: 598<pre> 599 re> /(tang|tangerine|tan)/g 600 data> yellow tangerine and tangy sultana\D 601 0: tangerine 602 1: tang 603 2: tan 604 0: tang 605 1: tan 606 0: tan 607</pre> 608Since the matching function does not support substring capture, the escape 609sequences that are concerned with captured substrings are not relevant. 610</P> 611<br><a name="SEC9" href="#TOC1">RESTARTING AFTER A PARTIAL MATCH</a><br> 612<P> 613When the alternative matching function has given the PCRE_ERROR_PARTIAL return, 614indicating that the subject partially matched the pattern, you can restart the 615match with additional subject data by means of the \R escape sequence. For 616example: 617<pre> 618 re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/ 619 data> 23ja\P\D 620 Partial match: 23ja 621 data> n05\R\D 622 0: n05 623</pre> 624For further information about partial matching, see the 625<a href="pcrepartial.html"><b>pcrepartial</b></a> 626documentation. 627</P> 628<br><a name="SEC10" href="#TOC1">CALLOUTS</a><br> 629<P> 630If the pattern contains any callout requests, <b>pcretest</b>'s callout function 631is called during matching. This works with both matching functions. By default, 632the called function displays the callout number, the start and current 633positions in the text at the callout time, and the next pattern item to be 634tested. For example, the output 635<pre> 636 --->pqrabcdef 637 0 ^ ^ \d 638</pre> 639indicates that callout number 0 occurred for a match attempt starting at the 640fourth character of the subject string, when the pointer was at the seventh 641character of the data, and when the next pattern item was \d. Just one 642circumflex is output if the start and current positions are the same. 643</P> 644<P> 645Callouts numbered 255 are assumed to be automatic callouts, inserted as a 646result of the <b>/C</b> pattern modifier. In this case, instead of showing the 647callout number, the offset in the pattern, preceded by a plus, is output. For 648example: 649<pre> 650 re> /\d?[A-E]\*/C 651 data> E* 652 --->E* 653 +0 ^ \d? 654 +3 ^ [A-E] 655 +8 ^^ \* 656 +10 ^ ^ 657 0: E* 658</pre> 659The callout function in <b>pcretest</b> returns zero (carry on matching) by 660default, but you can use a \C item in a data line (as described above) to 661change this. 662</P> 663<P> 664Inserting callouts can be helpful when using <b>pcretest</b> to check 665complicated regular expressions. For further information about callouts, see 666the 667<a href="pcrecallout.html"><b>pcrecallout</b></a> 668documentation. 669</P> 670<br><a name="SEC11" href="#TOC1">NON-PRINTING CHARACTERS</a><br> 671<P> 672When <b>pcretest</b> is outputting text in the compiled version of a pattern, 673bytes other than 32-126 are always treated as non-printing characters are are 674therefore shown as hex escapes. 675</P> 676<P> 677When <b>pcretest</b> is outputting text that is a matched part of a subject 678string, it behaves in the same way, unless a different locale has been set for 679the pattern (using the <b>/L</b> modifier). In this case, the <b>isprint()</b> 680function to distinguish printing and non-printing characters. 681</P> 682<br><a name="SEC12" href="#TOC1">SAVING AND RELOADING COMPILED PATTERNS</a><br> 683<P> 684The facilities described in this section are not available when the POSIX 685inteface to PCRE is being used, that is, when the <b>/P</b> pattern modifier is 686specified. 687</P> 688<P> 689When the POSIX interface is not in use, you can cause <b>pcretest</b> to write a 690compiled pattern to a file, by following the modifiers with > and a file name. 691For example: 692<pre> 693 /pattern/im >/some/file 694</pre> 695See the 696<a href="pcreprecompile.html"><b>pcreprecompile</b></a> 697documentation for a discussion about saving and re-using compiled patterns. 698</P> 699<P> 700The data that is written is binary. The first eight bytes are the length of the 701compiled pattern data followed by the length of the optional study data, each 702written as four bytes in big-endian order (most significant byte first). If 703there is no study data (either the pattern was not studied, or studying did not 704return any data), the second length is zero. The lengths are followed by an 705exact copy of the compiled pattern. If there is additional study data, this 706follows immediately after the compiled pattern. After writing the file, 707<b>pcretest</b> expects to read a new pattern. 708</P> 709<P> 710A saved pattern can be reloaded into <b>pcretest</b> by specifing < and a file 711name instead of a pattern. The name of the file must not contain a < character, 712as otherwise <b>pcretest</b> will interpret the line as a pattern delimited by < 713characters. 714For example: 715<pre> 716 re> </some/file 717 Compiled regex loaded from /some/file 718 No study data 719</pre> 720When the pattern has been loaded, <b>pcretest</b> proceeds to read data lines in 721the usual way. 722</P> 723<P> 724You can copy a file written by <b>pcretest</b> to a different host and reload it 725there, even if the new host has opposite endianness to the one on which the 726pattern was compiled. For example, you can compile on an i86 machine and run on 727a SPARC machine. 728</P> 729<P> 730File names for saving and reloading can be absolute or relative, but note that 731the shell facility of expanding a file name that starts with a tilde (~) is not 732available. 733</P> 734<P> 735The ability to save and reload files in <b>pcretest</b> is intended for testing 736and experimentation. It is not intended for production use because only a 737single pattern can be written to a file. Furthermore, there is no facility for 738supplying custom character tables for use with a reloaded pattern. If the 739original pattern was compiled with custom tables, an attempt to match a subject 740string using a reloaded pattern is likely to cause <b>pcretest</b> to crash. 741Finally, if you attempt to load a file that is not in the correct format, the 742result is undefined. 743</P> 744<br><a name="SEC13" href="#TOC1">SEE ALSO</a><br> 745<P> 746<b>pcre</b>(3), <b>pcreapi</b>(3), <b>pcrecallout</b>(3), <b>pcrematching</b>(3), 747<b>pcrepartial</b>(d), <b>pcrepattern</b>(3), <b>pcreprecompile</b>(3). 748</P> 749<br><a name="SEC14" href="#TOC1">AUTHOR</a><br> 750<P> 751Philip Hazel 752<br> 753University Computing Service 754<br> 755Cambridge CB2 3QH, England. 756<br> 757</P> 758<br><a name="SEC15" href="#TOC1">REVISION</a><br> 759<P> 760Last updated: 21 November 2010 761<br> 762Copyright © 1997-2010 University of Cambridge. 763<br> 764<p> 765Return to the <a href="index.html">PCRE index page</a>. 766</p> 767