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1    PCRETEST(1)                                                        PCRETEST(1)
2    
3    
4  NAME  NAME
5       pcretest - a program  for  testing  Perl-compatible  regular         pcretest - a program for testing Perl-compatible regular expressions.
      expressions.  
6    
7    
8  SYNOPSIS  SYNOPSIS
      pcretest [-d] [-i] [-m] [-o osize] [-p] [-t] [source]  [des-  
      tination]  
9    
10       pcretest was written as a test program for the PCRE  regular         pcretest [options] [source] [destination]
11       expression  library  itself,  but  it  can  also be used for  
12       experimenting  with  regular  expressions.   This   document         pcretest  was written as a test program for the PCRE regular expression
13       describes  the  features of the test program; for details of         library itself, but it can also be used for experimenting with  regular
14       the regular  expressions  themselves,  see  the  pcrepattern         expressions.  This document describes the features of the test program;
15       documentation.  For details of PCRE and its options, see the         for details of the regular expressions themselves, see the  pcrepattern
16       pcreapi documentation.         documentation. For details of the PCRE library function calls and their
17           options, see the pcreapi documentation.
18    
19    
20  OPTIONS  OPTIONS
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         -C        Output the version number of the PCRE library, and all avail-
26                 all   available  information  about  the  optional                   able  information  about  the  optional  features  that   are
27                 features that are included, and then exit.                   included, and then exit.
28    
29       -d        Behave as if each regex had the /D  modifier  (see         -d        Behave  as  if  each  regex  has the /D (debug) modifier; the
30                 below); the internal form is output after compila-                   internal form and information about the compiled  pattern  is
31                 tion.                   output after compilation; -d is equivalent to -b -i.
32    
33       -i        Behave as if  each  regex  had  the  /I  modifier;         -dfa      Behave  as if each data line contains the \D escape sequence;
34                 information  about  the  compiled pattern is given                   this    causes    the    alternative    matching    function,
35                 after compilation.                   pcre_dfa_exec(),   to   be   used  instead  of  the  standard
36                     pcre_exec() function (more detail is given below).
37       -m        Output the size of each compiled pattern after  it  
38                 has been compiled. This is equivalent to adding /M         -help     Output a brief summary these options and then exit.
39                 to each regular expression. For compatibility with  
40                 earlier  versions of pcretest, -s is a synonym for         -i        Behave as if each regex  has  the  /I  modifier;  information
41                 -m.                   about the compiled pattern is given after compilation.
42    
43       -o osize  Set the number of elements in  the  output  vector         -m        Output  the  size  of each compiled pattern after it has been
44                 that  is  used  when calling PCRE to be osize. The                   compiled. This is equivalent to adding  /M  to  each  regular
45                 default value is 45, which is enough for  14  cap-                   expression.   For  compatibility  with  earlier  versions  of
46                 turing  subexpressions.  The  vector  size  can be                   pcretest, -s is a synonym for -m.
47                 changed for individual matching calls by including  
48                 \O in the data line (see below).         -o osize  Set the number of elements in the output vector that is  used
49                     when  calling pcre_exec() or pcre_dfa_exec() to be osize. The
50       -p        Behave as if each regex has /P modifier; the POSIX                   default value is 45, which is enough for 14 capturing  subex-
51                 wrapper  API  is  used  to  call PCRE. None of the                   pressions   for  pcre_exec()  or  22  different  matches  for
52                 other options has any effect when -p is set.                   pcre_dfa_exec(). The vector size can be changed for  individ-
53                     ual  matching  calls  by  including  \O in the data line (see
54       -t        Run each compile, study, and match many times with                   below).
55                 a  timer, and output resulting time per compile or  
56                 match (in milliseconds). Do not set  -t  with  -m,         -p        Behave as if each regex has the /P modifier; the POSIX  wrap-
57                 because  you  will  then get the size output 20000                   per  API  is used to call PCRE. None of the other options has
58                 times and the timing will be distorted.                   any effect when -p is set.
59    
60           -q        Do not output the version number of pcretest at the start  of
61                     execution.
62    
63           -S size   On  Unix-like  systems,  set the size of the runtime stack to
64                     size megabytes.
65    
66           -t        Run each compile, study, and match many times with  a  timer,
67                     and  output resulting time per compile or match (in millisec-
68                     onds). Do not set -m with -t, because you will then  get  the
69                     size  output  a  zillion  times,  and the timing will be dis-
70                     torted. You can control the number  of  iterations  that  are
71                     used  for timing by following -t with a number (as a separate
72                     item on the command line). For example, "-t 1000" would iter-
73                     ate 1000 times. The default is to iterate 500000 times.
74    
75           -tm       This is like -t except that it times only the matching phase,
76                     not the compile or study phases.
77    
78    
79  DESCRIPTION  DESCRIPTION
80    
81       If pcretest is given two filename arguments, it  reads  from         If pcretest is given two filename arguments, it reads  from  the  first
82       the  first and writes to the second. If it is given only one         and writes to the second. If it is given only one filename argument, it
83       filename argument, it reads from that  file  and  writes  to         reads from that file and writes to stdout.  Otherwise,  it  reads  from
84       stdout. Otherwise, it reads from stdin and writes to stdout,         stdin  and  writes to stdout, and prompts for each line of input, using
85       and prompts for each line of input, using  "re>"  to  prompt         "re>" to prompt for regular expressions, and "data>" to prompt for data
86       for  regular  expressions,  and  "data>"  to prompt for data         lines.
87       lines.  
88           The program handles any number of sets of input on a single input file.
89       The program handles any number of sets of input on a  single         Each set starts with a regular expression, and continues with any  num-
90       input  file.  Each set starts with a regular expression, and         ber of data lines to be matched against the pattern.
91       continues with any  number  of  data  lines  to  be  matched  
92       against the pattern.         Each  data line is matched separately and independently. If you want to
93           do multi-line matches, you have to use the \n escape sequence (or \r or
94       Each line is matched separately and  independently.  If  you         \r\n, etc., depending on the newline setting) in a single line of input
95       want  to  do  multiple-line  matches, you have to use the \n         to encode the newline sequences. There is no limit  on  the  length  of
96       escape sequence in a single line of input to encode the new-         data  lines;  the  input  buffer is automatically extended if it is too
97       line  characters.  The maximum length of data line is 30,000         small.
98       characters.  
99           An empty line signals the end of the data lines, at which point  a  new
100       An empty line signals the end of the data  lines,  at  which         regular  expression is read. The regular expressions are given enclosed
101       point  a new regular expression is read. The regular expres-         in any non-alphanumeric delimiters other than backslash, for example:
102       sions are given enclosed in  any  non-alphameric  delimiters  
103       other than backslash, for example           /(a|bc)x+yz/
104    
105         /(a|bc)x+yz/         White space before the initial delimiter is ignored. A regular  expres-
106           sion  may be continued over several input lines, in which case the new-
107       White space before the initial delimiter is ignored. A regu-         line characters are included within it. It is possible to  include  the
108       lar expression may be continued over several input lines, in         delimiter within the pattern by escaping it, for example
109       which case the newline characters are included within it. It  
110       is  possible  to include the delimiter within the pattern by           /abc\/def/
111       escaping it, for example  
112           If  you  do  so, the escape and the delimiter form part of the pattern,
113         /abc\/def/         but since delimiters are always non-alphanumeric, this does not  affect
114           its  interpretation.   If the terminating delimiter is immediately fol-
115       If you do so, the escape and the delimiter form part of  the         lowed by a backslash, for example,
116       pattern,  but  since  delimiters  are always non-alphameric,  
117       this does not affect its interpretation.  If the terminating           /abc/\
118       delimiter  is immediately followed by a backslash, for exam-  
119       ple,         then a backslash is added to the end of the pattern. This  is  done  to
120           provide  a  way of testing the error condition that arises if a pattern
121         /abc/\         finishes with a backslash, because
122    
123       then a backslash is added to the end of the pattern. This is           /abc\/
124       done  to  provide  a way of testing the error condition that  
125       arises if a pattern finishes with a backslash, because         is interpreted as the first line of a pattern that starts with  "abc/",
126           causing pcretest to read the next line as a continuation of the regular
127         /abc\/         expression.
   
      is interpreted as the first line of a  pattern  that  starts  
      with  "abc/",  causing  pcretest  to read the next line as a  
      continuation of the regular expression.  
128    
129    
130  PATTERN MODIFIERS  PATTERN MODIFIERS
131    
132       The pattern may be followed by i, m, s,  or  x  to  set  the         A pattern may be followed by any number of modifiers, which are  mostly
133       PCRE_CASELESS, PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED         single  characters.  Following  Perl usage, these are referred to below
134       options, respectively. For example:         as, for example, "the /i modifier", even though the  delimiter  of  the
135           pattern  need  not always be a slash, and no slash is used when writing
136         /caseless/i         modifiers. Whitespace may appear between the  final  pattern  delimiter
137           and the first modifier, and between the modifiers themselves.
138       These modifier letters have the same effect as  they  do  in  
139       Perl.  There  are  others  that set PCRE options that do not         The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,
140       correspond to anything in Perl:  /A, /E, /N, /U, and /X  set         PCRE_DOTALL, or PCRE_EXTENDED  options,  respectively,  when  pcre_com-
141       PCRE_ANCHORED,   PCRE_DOLLAR_ENDONLY,  PCRE_NO_AUTO_CAPTURE,         pile()  is  called. These four modifier letters have the same effect as
142       PCRE_UNGREEDY, and PCRE_EXTRA respectively.         they do in Perl. For example:
143    
144       Searching for  all  possible  matches  within  each  subject           /caseless/i
145       string  can  be  requested  by  the /g or /G modifier. After  
146       finding  a  match,  PCRE  is  called  again  to  search  the         The following table shows additional modifiers for setting PCRE options
147       remainder  of  the subject string. The difference between /g         that do not correspond to anything in Perl:
148       and /G is that the former uses the startoffset  argument  to  
149       pcre_exec()  to  start  searching  at a new point within the           /A       PCRE_ANCHORED
150       entire string (which is in effect what Perl  does),  whereas           /C       PCRE_AUTO_CALLOUT
151       the  latter  passes over a shortened substring. This makes a           /E       PCRE_DOLLAR_ENDONLY
152       difference to the matching process  if  the  pattern  begins           /f       PCRE_FIRSTLINE
153       with a lookbehind assertion (including \b or \B).           /J       PCRE_DUPNAMES
154             /N       PCRE_NO_AUTO_CAPTURE
155       If any call to pcre_exec() in a /g or /G sequence matches an           /U       PCRE_UNGREEDY
156       empty  string,  the next call is done with the PCRE_NOTEMPTY           /X       PCRE_EXTRA
157       and PCRE_ANCHORED flags set in order to search for  another,           /<cr>    PCRE_NEWLINE_CR
158       non-empty,  match  at  the same point.  If this second match           /<lf>    PCRE_NEWLINE_LF
159       fails, the start offset is advanced by one, and  the  normal           /<crlf>  PCRE_NEWLINE_CRLF
160       match  is  retried.  This imitates the way Perl handles such           /<any>   PCRE_NEWLINE_ANY
161       cases when using the /g modifier or the split() function.  
162           Those  specifying  line ending sequencess are literal strings as shown.
163       There are a number of other modifiers  for  controlling  the         This example sets multiline matching  with  CRLF  as  the  line  ending
164       way pcretest operates.         sequence:
165    
166       The /+ modifier requests that as well as outputting the sub-           /^abc/m<crlf>
167       string  that  matched the entire pattern, pcretest should in  
168       addition output the remainder of the subject string. This is         Details  of the meanings of these PCRE options are given in the pcreapi
169       useful  for tests where the subject contains multiple copies         documentation.
170       of the same substring.  
171       Finding all matches in a string
172       The /L modifier must be followed directly by the name  of  a  
173       locale, for example,         Searching for all possible matches within each subject  string  can  be
174           requested  by  the  /g  or  /G modifier. After finding a match, PCRE is
175         /pattern/Lfr         called again to search the remainder of the subject string. The differ-
176           ence between /g and /G is that the former uses the startoffset argument
177       For this reason, it must be the last  modifier  letter.  The         to pcre_exec() to start searching at a  new  point  within  the  entire
178       given  locale is set, pcre_maketables() is called to build a         string  (which  is in effect what Perl does), whereas the latter passes
179       set of character tables for the locale,  and  this  is  then         over a shortened substring. This makes a  difference  to  the  matching
180       passed  to pcre_compile() when compiling the regular expres-         process if the pattern begins with a lookbehind assertion (including \b
181       sion. Without an /L modifier, NULL is passed as  the  tables         or \B).
182       pointer; that is, /L applies only to the expression on which  
183       it appears.         If any call to pcre_exec() in a /g or  /G  sequence  matches  an  empty
184           string,  the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED
185       The /I modifier requests that  pcretest  output  information         flags set in order to search for another, non-empty, match at the  same
186       about the compiled expression (whether it is anchored, has a         point.   If  this  second  match fails, the start offset is advanced by
187       fixed first character, and so on). It does this  by  calling         one, and the normal match is retried. This imitates the way  Perl  han-
188       pcre_fullinfo()  after  compiling an expression, and output-         dles such cases when using the /g modifier or the split() function.
189       ting the information it gets back. If the  pattern  is  stu-  
190       died, the results of that are also output.     Other modifiers
191    
192       The /D modifier is a  PCRE  debugging  feature,  which  also         There are yet more modifiers for controlling the way pcretest operates.
193       assumes /I.  It causes the internal form of compiled regular  
194       expressions to be output after compilation. If  the  pattern         The /+ modifier requests that as well as outputting the substring  that
195       was studied, the information returned is also output.         matched  the  entire  pattern,  pcretest  should in addition output the
196           remainder of the subject string. This is useful  for  tests  where  the
197       The /S modifier causes pcre_study() to be called  after  the         subject contains multiple copies of the same substring.
198       expression  has been compiled, and the results used when the  
199       expression is matched.         The  /B modifier is a debugging feature. It requests that pcretest out-
200           put a representation of the compiled byte code after compilation.
201       The /M modifier causes the size of memory block used to hold  
202       the compiled pattern to be output.         The /L modifier must be followed directly by the name of a locale,  for
203           example,
204       The /P modifier causes pcretest to call PCRE via  the  POSIX  
205       wrapper  API  rather than its native API. When this is done,           /pattern/Lfr_FR
206       all other modifiers except  /i,  /m,  and  /+  are  ignored.  
207       REG_ICASE is set if /i is present, and REG_NEWLINE is set if         For this reason, it must be the last modifier. The given locale is set,
208       /m    is    present.    The    wrapper    functions    force         pcre_maketables() is called to build a set of character tables for  the
209       PCRE_DOLLAR_ENDONLY    always,    and   PCRE_DOTALL   unless         locale,  and  this  is then passed to pcre_compile() when compiling the
210       REG_NEWLINE is set.         regular expression. Without an /L  modifier,  NULL  is  passed  as  the
211           tables  pointer; that is, /L applies only to the expression on which it
212       The /8 modifier  causes  pcretest  to  call  PCRE  with  the         appears.
213       PCRE_UTF8  option set. This turns on support for UTF-8 char-  
214       acter handling in PCRE, provided that it was  compiled  with         The /I modifier requests that pcretest  output  information  about  the
215       this  support  enabled.  This  modifier also causes any non-         compiled  pattern (whether it is anchored, has a fixed first character,
216       printing characters in output strings to  be  printed  using         and so on). It does this by calling pcre_fullinfo() after  compiling  a
217       the \x{hh...} notation if they are valid UTF-8 sequences.         pattern.  If  the pattern is studied, the results of that are also out-
218           put.
219       If the /? modifier is used with /8, it  causes  pcretest  to  
220       call  pcre_compile()  with the PCRE_NO_UTF8_CHECK option, to         The /D modifier is a PCRE debugging feature, and is equivalent to  /BI,
221       suppress the checking of the string for UTF-8 validity.         that is, both the /B and the /I modifiers.
222    
223           The /F modifier causes pcretest to flip the byte order of the fields in
224           the compiled pattern that  contain  2-byte  and  4-byte  numbers.  This
225           facility  is  for testing the feature in PCRE that allows it to execute
226           patterns that were compiled on a host with a different endianness. This
227           feature  is  not  available  when  the POSIX interface to PCRE is being
228           used, that is, when the /P pattern modifier is specified. See also  the
229           section about saving and reloading compiled patterns below.
230    
231           The  /S  modifier causes pcre_study() to be called after the expression
232           has been compiled, and the results used when the expression is matched.
233    
234           The  /M  modifier causes the size of memory block used to hold the com-
235           piled pattern to be output.
236    
237           The /P modifier causes pcretest to call PCRE via the POSIX wrapper  API
238           rather  than  its  native  API.  When this is done, all other modifiers
239           except /i, /m, and /+ are ignored. REG_ICASE is set if /i  is  present,
240           and  REG_NEWLINE  is  set if /m is present. The wrapper functions force
241           PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is  set.
242    
243           The  /8 modifier causes pcretest to call PCRE with the PCRE_UTF8 option
244           set. This turns on support for UTF-8 character handling in  PCRE,  pro-
245           vided  that  it  was  compiled with this support enabled. This modifier
246           also causes any non-printing characters in output strings to be printed
247           using the \x{hh...} notation if they are valid UTF-8 sequences.
248    
249           If  the  /?  modifier  is  used  with  /8,  it  causes pcretest to call
250           pcre_compile() with the  PCRE_NO_UTF8_CHECK  option,  to  suppress  the
251           checking of the string for UTF-8 validity.
252    
253    
254    DATA LINES
255    
256           Before  each  data  line is passed to pcre_exec(), leading and trailing
257           whitespace is removed, and it is then scanned for \  escapes.  Some  of
258           these  are  pretty esoteric features, intended for checking out some of
259           the more complicated features of PCRE. If you are just  testing  "ordi-
260           nary"  regular  expressions,  you probably don't need any of these. The
261           following escapes are recognized:
262    
263             \a         alarm (BEL, \x07)
264             \b         backspace (\x08)
265             \e         escape (\x27)
266             \f         formfeed (\x0c)
267             \n         newline (\x0a)
268             \qdd       set the PCRE_MATCH_LIMIT limit to dd
269                          (any number of digits)
270             \r         carriage return (\x0d)
271             \t         tab (\x09)
272             \v         vertical tab (\x0b)
273             \nnn       octal character (up to 3 octal digits)
274             \xhh       hexadecimal character (up to 2 hex digits)
275             \x{hh...}  hexadecimal character, any number of digits
276                          in UTF-8 mode
277             \A         pass the PCRE_ANCHORED option to pcre_exec()
278                          or pcre_dfa_exec()
279             \B         pass the PCRE_NOTBOL option to pcre_exec()
280                          or pcre_dfa_exec()
281             \Cdd       call pcre_copy_substring() for substring dd
282                          after a successful match (number less than 32)
283             \Cname     call pcre_copy_named_substring() for substring
284                          "name" after a successful match (name termin-
285                          ated by next non alphanumeric character)
286             \C+        show the current captured substrings at callout
287                          time
288             \C-        do not supply a callout function
289             \C!n       return 1 instead of 0 when callout number n is
290                          reached
291             \C!n!m     return 1 instead of 0 when callout number n is
292                          reached for the nth time
293             \C*n       pass the number n (may be negative) as callout
294                          data; this is used as the callout return value
295             \D         use the pcre_dfa_exec() match function
296             \F         only shortest match for pcre_dfa_exec()
297             \Gdd       call pcre_get_substring() for substring dd
298                          after a successful match (number less than 32)
299             \Gname     call pcre_get_named_substring() for substring
300                          "name" after a successful match (name termin-
301                          ated by next non-alphanumeric character)
302             \L         call pcre_get_substringlist() after a
303                          successful match
304             \M         discover the minimum MATCH_LIMIT and
305                          MATCH_LIMIT_RECURSION settings
306             \N         pass the PCRE_NOTEMPTY option to pcre_exec()
307                          or pcre_dfa_exec()
308             \Odd       set the size of the output vector passed to
309                          pcre_exec() to dd (any number of digits)
310             \P         pass the PCRE_PARTIAL option to pcre_exec()
311                          or pcre_dfa_exec()
312             \Qdd       set the PCRE_MATCH_LIMIT_RECURSION limit to dd
313                          (any number of digits)
314             \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()
315             \S         output details of memory get/free calls during matching
316             \Z         pass the PCRE_NOTEOL option to pcre_exec()
317                          or pcre_dfa_exec()
318             \?         pass the PCRE_NO_UTF8_CHECK option to
319                          pcre_exec() or pcre_dfa_exec()
320             \>dd       start the match at offset dd (any number of digits);
321                          this sets the startoffset argument for pcre_exec()
322                          or pcre_dfa_exec()
323             \<cr>      pass the PCRE_NEWLINE_CR option to pcre_exec()
324                          or pcre_dfa_exec()
325             \<lf>      pass the PCRE_NEWLINE_LF option to pcre_exec()
326                          or pcre_dfa_exec()
327             \<crlf>    pass the PCRE_NEWLINE_CRLF option to pcre_exec()
328                          or pcre_dfa_exec()
329             \<any>     pass the PCRE_NEWLINE_ANY option to pcre_exec()
330                          or pcre_dfa_exec()
331    
332           The escapes that specify line ending  sequences  are  literal  strings,
333           exactly as shown. No more than one newline setting should be present in
334           any data line.
335    
336           A backslash followed by anything else just escapes the  anything  else.
337           If  the very last character is a backslash, it is ignored. This gives a
338           way of passing an empty line as data, since a real  empty  line  termi-
339           nates the data input.
340    
341           If  \M  is present, pcretest calls pcre_exec() several times, with dif-
342           ferent values in the match_limit and  match_limit_recursion  fields  of
343           the  pcre_extra  data structure, until it finds the minimum numbers for
344           each parameter that allow pcre_exec() to complete. The match_limit num-
345           ber  is  a  measure of the amount of backtracking that takes place, and
346           checking it out can be instructive. For most simple matches, the number
347           is  quite  small,  but for patterns with very large numbers of matching
348           possibilities, it can become large very quickly with increasing  length
349           of subject string. The match_limit_recursion number is a measure of how
350           much stack (or, if PCRE is compiled with  NO_RECURSE,  how  much  heap)
351           memory is needed to complete the match attempt.
352    
353           When  \O  is  used, the value specified may be higher or lower than the
354           size set by the -O command line option (or defaulted to 45); \O applies
355           only to the call of pcre_exec() for the line in which it appears.
356    
357           If  the /P modifier was present on the pattern, causing the POSIX wrap-
358           per API to be used, the only option-setting  sequences  that  have  any
359           effect  are \B and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively,
360           to be passed to regexec().
361    
362           The use of \x{hh...} to represent UTF-8 characters is not dependent  on
363           the  use  of  the  /8 modifier on the pattern. It is recognized always.
364           There may be any number of hexadecimal digits inside  the  braces.  The
365           result  is from one to six bytes, encoded according to the UTF-8 rules.
366    
367    
368    THE ALTERNATIVE MATCHING FUNCTION
369    
370           By  default,  pcretest  uses  the  standard  PCRE  matching   function,
371           pcre_exec() to match each data line. From release 6.0, PCRE supports an
372           alternative matching function, pcre_dfa_test(),  which  operates  in  a
373           different  way,  and has some restrictions. The differences between the
374           two functions are described in the pcrematching documentation.
375    
376           If a data line contains the \D escape sequence, or if the command  line
377           contains  the -dfa option, the alternative matching function is called.
378           This function finds all possible matches at a given point. If, however,
379           the  \F escape sequence is present in the data line, it stops after the
380           first match is found. This is always the shortest possible match.
381    
382    
383    DEFAULT OUTPUT FROM PCRETEST
384    
385           This section describes the output when the  normal  matching  function,
386           pcre_exec(), is being used.
387    
388           When a match succeeds, pcretest outputs the list of captured substrings
389           that pcre_exec() returns, starting with number 0 for  the  string  that
390           matched the whole pattern. Otherwise, it outputs "No match" or "Partial
391           match" when pcre_exec() returns PCRE_ERROR_NOMATCH  or  PCRE_ERROR_PAR-
392           TIAL,  respectively, and otherwise the PCRE negative error number. Here
393           is an example of an interactive pcretest run.
394    
395             $ pcretest
396             PCRE version 7.0 30-Nov-2006
397    
398               re> /^abc(\d+)/
399             data> abc123
400              0: abc123
401              1: 123
402             data> xyz
403             No match
404    
405           If the strings contain any non-printing characters, they are output  as
406           \0x  escapes,  or  as \x{...} escapes if the /8 modifier was present on
407           the pattern. See below for the definition of  non-printing  characters.
408           If  the pattern has the /+ modifier, the output for substring 0 is fol-
409           lowed by the the rest of the subject string, identified  by  "0+"  like
410           this:
411    
412               re> /cat/+
413             data> cataract
414              0: cat
415              0+ aract
416    
417           If  the  pattern  has  the /g or /G modifier, the results of successive
418           matching attempts are output in sequence, like this:
419    
420               re> /\Bi(\w\w)/g
421             data> Mississippi
422              0: iss
423              1: ss
424              0: iss
425              1: ss
426              0: ipp
427              1: pp
428    
429           "No match" is output only if the first match attempt fails.
430    
431           If any of the sequences \C, \G, or \L are present in a data  line  that
432           is  successfully  matched,  the substrings extracted by the convenience
433           functions are output with C, G, or L after the string number instead of
434           a colon. This is in addition to the normal full list. The string length
435           (that is, the return from the extraction function) is given  in  paren-
436           theses after each string for \C and \G.
437    
438           Note that whereas patterns can be continued over several lines (a plain
439           ">" prompt is used for continuations), data lines may not. However new-
440           lines  can  be included in data by means of the \n escape (or \r, \r\n,
441           etc., depending on the newline sequence setting).
442    
443    
444    OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
445    
446           When the alternative matching function, pcre_dfa_exec(),  is  used  (by
447           means  of  the \D escape sequence or the -dfa command line option), the
448           output consists of a list of all the matches that start  at  the  first
449           point in the subject where there is at least one match. For example:
450    
451               re> /(tang|tangerine|tan)/
452             data> yellow tangerine\D
453              0: tangerine
454              1: tang
455              2: tan
456    
457           (Using  the  normal  matching function on this data finds only "tang".)
458           The longest matching string is always given first (and numbered  zero).
459    
460           If /g is present on the pattern, the search for further matches resumes
461           at the end of the longest match. For example:
462    
463               re> /(tang|tangerine|tan)/g
464             data> yellow tangerine and tangy sultana\D
465              0: tangerine
466              1: tang
467              2: tan
468              0: tang
469              1: tan
470              0: tan
471    
472           Since the matching function does not  support  substring  capture,  the
473           escape  sequences  that  are concerned with captured substrings are not
474           relevant.
475    
476    
477    RESTARTING AFTER A PARTIAL MATCH
478    
479           When the alternative matching function has given the PCRE_ERROR_PARTIAL
480           return,  indicating that the subject partially matched the pattern, you
481           can restart the match with additional subject data by means of  the  \R
482           escape sequence. For example:
483    
484               re> /^?(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)$/
485             data> 23ja\P\D
486             Partial match: 23ja
487             data> n05\R\D
488              0: n05
489    
490           For  further  information  about  partial matching, see the pcrepartial
491           documentation.
492    
493    
494  CALLOUTS  CALLOUTS
495    
496       If the pattern contains  any  callout  requests,  pcretest's         If the pattern contains any callout requests, pcretest's callout  func-
497       callout function will be called. By default, it displays the         tion  is  called  during  matching. This works with both matching func-
498       callout number, and the start and current positions  in  the         tions. By default, the called function displays the callout number, the
499       text at the callout time. For example, the output         start  and  current  positions in the text at the callout time, and the
500           next pattern item to be tested. For example, the output
501         --->pqrabcdef  
502           0    ^  ^           --->pqrabcdef
503               0    ^  ^     \d
504       indicates that callout number 0 occurred for a match attempt  
505       starting at the fourth character of the subject string, when         indicates that callout number 0 occurred for a match  attempt  starting
506       the pointer was at the seventh character. The callout  func-         at  the fourth character of the subject string, when the pointer was at
507       tion returns zero (carry on matching) by default.         the seventh character of the data, and when the next pattern  item  was
508           \d.  Just  one  circumflex is output if the start and current positions
509       Inserting callouts may be helpful  when  using  pcretest  to         are the same.
510       check  complicated regular expressions. For further informa-  
511       tion about callouts, see the pcrecallout documentation.         Callouts numbered 255 are assumed to be automatic callouts, inserted as
512           a  result  of the /C pattern modifier. In this case, instead of showing
513       For testing the PCRE library, additional control of  callout         the callout number, the offset in the pattern, preceded by a  plus,  is
514       behaviour  is available via escape sequences in the data, as         output. For example:
515       described in the following section.  In  particular,  it  is  
516       possible to pass in a number as callout data (the default is             re> /\d?[A-E]\*/C
517       zero). If the callout function receives a  non-zero  number,           data> E*
518       it returns that value instead of zero.           --->E*
519              +0 ^      \d?
520              +3 ^      [A-E]
521              +8 ^^     \*
522             +10 ^ ^
523              0: E*
524    
525           The  callout  function  in pcretest returns zero (carry on matching) by
526           default, but you can use a \C item in a data line (as described  above)
527           to change this.
528    
529           Inserting  callouts can be helpful when using pcretest to check compli-
530           cated regular expressions. For further information about callouts,  see
531           the pcrecallout documentation.
532    
533    
534    NON-PRINTING CHARACTERS
535    
536           When  pcretest is outputting text in the compiled version of a pattern,
537           bytes other than 32-126 are always treated as  non-printing  characters
538           are are therefore shown as hex escapes.
539    
540           When  pcretest  is  outputting text that is a matched part of a subject
541           string, it behaves in the same way, unless a different locale has  been
542           set  for  the  pattern  (using  the  /L  modifier).  In  this case, the
543           isprint() function to distinguish printing and non-printing characters.
544    
545    
546    SAVING AND RELOADING COMPILED PATTERNS
547    
548           The  facilities  described  in  this section are not available when the
549           POSIX inteface to PCRE is being used, that is, when the /P pattern mod-
550           ifier is specified.
551    
552           When the POSIX interface is not in use, you can cause pcretest to write
553           a compiled pattern to a file, by following the modifiers with >  and  a
554           file name.  For example:
555    
556             /pattern/im >/some/file
557    
558           See  the pcreprecompile documentation for a discussion about saving and
559           re-using compiled patterns.
560    
561           The data that is written is binary.  The  first  eight  bytes  are  the
562           length  of  the  compiled  pattern  data  followed by the length of the
563           optional study data, each written as four  bytes  in  big-endian  order
564           (most  significant  byte  first). If there is no study data (either the
565           pattern was not studied, or studying did not return any data), the sec-
566           ond  length  is  zero. The lengths are followed by an exact copy of the
567           compiled pattern. If there is additional study data, this follows imme-
568           diately  after  the  compiled pattern. After writing the file, pcretest
569           expects to read a new pattern.
570    
571           A saved pattern can be reloaded into pcretest by specifing < and a file
572           name  instead  of  a pattern. The name of the file must not contain a <
573           character, as otherwise pcretest will interpret the line as  a  pattern
574           delimited by < characters.  For example:
575    
576              re> </some/file
577             Compiled regex loaded from /some/file
578             No study data
579    
580           When  the pattern has been loaded, pcretest proceeds to read data lines
581           in the usual way.
582    
583           You can copy a file written by pcretest to a different host and  reload
584           it  there,  even  if the new host has opposite endianness to the one on
585           which the pattern was compiled. For example, you can compile on an  i86
586           machine and run on a SPARC machine.
587    
588           File  names  for  saving and reloading can be absolute or relative, but
589           note that the shell facility of expanding a file name that starts  with
590           a tilde (~) is not available.
591    
592           The  ability to save and reload files in pcretest is intended for test-
593           ing and experimentation. It is not intended for production use  because
594           only  a  single pattern can be written to a file. Furthermore, there is
595           no facility for supplying  custom  character  tables  for  use  with  a
596           reloaded  pattern.  If  the  original  pattern was compiled with custom
597           tables, an attempt to match a subject string using a  reloaded  pattern
598           is  likely to cause pcretest to crash.  Finally, if you attempt to load
599           a file that is not in the correct format, the result is undefined.
600    
601    
602  DATA LINES  SEE ALSO
603    
604       Before each data line is passed to pcre_exec(), leading  and         pcre(3), pcreapi(3), pcrecallout(3),  pcrematching(3),  pcrepartial(d),
605       trailing whitespace is removed, and it is then scanned for \         pcrepattern(3), pcreprecompile(3).
      escapes.  Some  of  these  are  pretty  esoteric   features,  
      intended  for  checking  out  some  of  the more complicated  
      features of PCRE. If you are just testing "ordinary" regular  
      expressions,  you probably don't need any of these. The fol-  
      lowing escapes are recognized:  
   
        \a         alarm (= BEL)  
        \b         backspace  
        \e         escape  
        \f         formfeed  
        \n         newline  
        \r         carriage return  
        \t         tab  
        \v         vertical tab  
        \nnn       octal character (up to 3 octal digits)  
        \xhh       hexadecimal character (up to 2 hex digits)  
        \x{hh...}  hexadecimal character, any number of digits  
                     in UTF-8 mode  
        \A         pass the PCRE_ANCHORED option to pcre_exec()  
        \B         pass the PCRE_NOTBOL option to pcre_exec()  
        \Cdd       call pcre_copy_substring() for substring dd  
                     after a successful match (any decimal number  
                     less than 32)  
        \Cname     call pcre_copy_named_substring() for substring  
   
                     "name" after a successful match (name termin-  
                     ated by next non alphanumeric character)  
        \C+        show the current captured substrings at callout  
                     time  
        \C-        do not supply a callout function  
        \C!n       return 1 instead of 0 when callout number n is  
                     reached  
        \C!n!m     return 1 instead of 0 when callout number n is  
                     reached for the nth time  
        \C*n       pass the number n (may be negative) as callout  
                     data  
        \Gdd       call pcre_get_substring() for substring dd  
                     after a successful match (any decimal number  
                     less than 32)  
        \Gname     call pcre_get_named_substring() for substring  
                     "name" after a successful match (name termin-  
                     ated by next non-alphanumeric character)  
        \L         call pcre_get_substringlist() after a  
                     successful match  
        \M         discover the minimum MATCH_LIMIT setting  
        \N         pass the PCRE_NOTEMPTY option to pcre_exec()  
        \Odd       set the size of the output vector passed to  
                     pcre_exec() to dd (any number of decimal  
                     digits)  
        \Z         pass the PCRE_NOTEOL option to pcre_exec()  
        \?         pass the PCRE_NO_UTF8_CHECK option to  
                     pcre_exec()  
   
      If \M is present, pcretest calls pcre_exec() several  times,  
      with  different  values  in  the  match_limit  field  of the  
      pcre_extra data structure, until it finds the minimum number  
      that is needed for pcre_exec() to complete. This number is a  
      measure of the amount of  recursion  and  backtracking  that  
      takes  place,  and  checking  it out can be instructive. For  
      most simple matches, the number is quite small, but for pat-  
      terns  with very large numbers of matching possibilities, it  
      can become large very quickly with increasing length of sub-  
      ject string.  
   
      When \O is used, it may be higher or lower than the size set  
      by  the  -O  option (or defaulted to 45); \O applies only to  
      the call of pcre_exec() for the line in which it appears.  
   
      A backslash followed by anything else just escapes the  any-  
      thing else. If the very last character is a backslash, it is  
      ignored. This gives a way of passing an empty line as  data,  
      since a real empty line terminates the data input.  
   
      If /P was present on the regex, causing  the  POSIX  wrapper  
      API  to  be  used,  only  B,  and Z have any effect, causing  
      REG_NOTBOL and REG_NOTEOL to be passed to regexec()  respec-  
      tively.  
      The use of \x{hh...} to represent UTF-8  characters  is  not  
      dependent  on  the use of the /8 modifier on the pattern. It  
      is recognized always. There may be any number of hexadecimal  
      digits  inside  the  braces.  The  result is from one to six  
      bytes, encoded according to the UTF-8 rules.  
   
   
 OUTPUT FROM PCRETEST  
   
      When a match succeeds, pcretest outputs the list of captured  
      substrings  that pcre_exec() returns, starting with number 0  
      for the string that matched the whole pattern.  Here  is  an  
      example of an interactive pcretest run.  
   
        $ pcretest  
        PCRE version 4.00 08-Jan-2003  
   
          re> /^abc(\d+)/  
        data> abc123  
         0: abc123  
         1: 123  
        data> xyz  
        No match  
   
      If the strings contain any non-printing characters, they are  
      output  as  \0x  escapes,  or  as  \x{...} escapes if the /8  
      modifier was present on the pattern. If the pattern has  the  
      /+  modifier, then the output for substring 0 is followed by  
      the the rest of the subject string, identified by "0+"  like  
      this:  
   
          re> /cat/+  
        data> cataract  
         0: cat  
         0+ aract  
   
      If the pattern has the /g or /G  modifier,  the  results  of  
      successive  matching  attempts  are output in sequence, like  
      this:  
   
          re> /\Bi(\w\w)/g  
        data> Mississippi  
         0: iss  
         1: ss  
         0: iss  
         1: ss  
         0: ipp  
         1: pp  
   
      "No match" is output only if the first match attempt fails.  
   
      If any of the sequences \C, \G, or \L are present in a  data  
      line  that is successfully matched, the substrings extracted  
      by the convenience functions are output  with  C,  G,  or  L  
      after the string number instead of a colon. This is in addi-  
      tion to the normal full list. The string  length  (that  is,  
      the  return  from  the  extraction  function)  is  given  in  
      parentheses after each string for \C and \G.  
   
      Note that while patterns can be continued over several lines  
      (a  plain  ">" prompt is used for continuations), data lines  
      may not. However newlines can be included in data  by  means  
      of the \n escape.  
606    
607    
608  AUTHOR  AUTHOR
609    
610       Philip Hazel <ph10@cam.ac.uk>         Philip Hazel
611       University Computing Service,         University Computing Service
612       Cambridge CB2 3QG, England.         Cambridge CB2 3QH, England.
613    
614    
615    REVISION
616    
617  Last updated: 20 August 2003         Last updated: 06 March 2007
618  Copyright (c) 1997-2003 University of Cambridge.         Copyright (c) 1997-2007 University of Cambridge.

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