pcrepattern
documentation. For details of the PCRE library function calls and their options, see the HREF
pcreapi
documentation. . .
10 -b Behave as if each regex has the /B (show bytecode) modifier; the internal form is output after compilation.
10 -C Output the version number of the PCRE library, and all available information about the optional features that are included, and then exit.
10 -d Behave as if each regex has the /D (debug) modifier; the internal form and information about the compiled pattern is output after compilation; -d is equivalent to -b -i.
10 -dfa Behave as if each data line contains the \eD escape sequence; this causes the alternative matching function, pcre_dfa_exec(), to be used instead of the standard pcre_exec() function (more detail is given below).
10 -help Output a brief summary these options and then exit.
10 -i Behave as if each regex has the /I modifier; information about the compiled pattern is given after compilation.
10 -M Behave as if each data line contains the \eM escape sequence; this causes PCRE to discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings by calling pcre_exec() repeatedly with different limits.
10 -m Output the size of each compiled pattern after it has been compiled. This is equivalent to adding /M to each regular expression. For compatibility with earlier versions of pcretest, -s is a synonym for -m.
10 -o osize Set the number of elements in the output vector that is used when calling pcre_exec() or pcre_dfa_exec() to be osize. The default value is 45, which is enough for 14 capturing subexpressions for pcre_exec() or 22 different matches for pcre_dfa_exec(). The vector size can be changed for individual matching calls by including \eO in the data line (see below).
10 -p Behave as if each regex has the /P modifier; the POSIX wrapper API is used to call PCRE. None of the other options has any effect when -p is set.
10 -q Do not output the version number of pcretest at the start of execution.
10 -S size On Unix-like systems, set the size of the runtime stack to size megabytes.
10 -t Run each compile, study, and match many times with a timer, and output resulting time per compile or match (in milliseconds). Do not set -m with -t, because you will then get the size output a zillion times, and the timing will be distorted. You can control the number of iterations that are used for timing by following -t with a number (as a separate item on the command line). For example, "-t 1000" would iterate 1000 times. The default is to iterate 500000 times.
10 -tm This is like -t except that it times only the matching phase, not the compile or study phases. . .
When pcretest is built, a configuration option can specify that it should be linked with the libreadline library. When this is done, if the input is from a terminal, it is read using the readline() function. This provides line-editing and history facilities. The output from the -help option states whether or not readline() will be used.
The program handles any number of sets of input on a single input file. Each set starts with a regular expression, and continues with any number of data lines to be matched against the pattern.
Each data line is matched separately and independently. If you want to do multi-line matches, you have to use the \en escape sequence (or \er or \er\en, etc., depending on the newline setting) in a single line of input to encode the newline sequences. There is no limit on the length of data lines; the input buffer is automatically extended if it is too small.
An empty line signals the end of the data lines, at which point a new regular expression is read. The regular expressions are given enclosed in any non-alphanumeric delimiters other than backslash, for example: /(a|bc)x+yz/ White space before the initial delimiter is ignored. A regular expression may be continued over several input lines, in which case the newline characters are included within it. It is possible to include the delimiter within the pattern by escaping it, for example /abc\e/def/ If you do so, the escape and the delimiter form part of the pattern, but since delimiters are always non-alphanumeric, this does not affect its interpretation. If the terminating delimiter is immediately followed by a backslash, for example, /abc/\e then a backslash is added to the end of the pattern. This is done to provide a way of testing the error condition that arises if a pattern finishes with a backslash, because /abc\e/ 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. . .
The /i, /m, /s, and /x modifiers set the PCRE_CASELESS,
PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when
pcre_compile() is called. These four modifier letters have the same
effect as they do in Perl. For example:
/caseless/i
The following table shows additional modifiers for setting PCRE compile-time
options that do not correspond to anything in Perl:
/8 PCRE_UTF8
/? PCRE_NO_UTF8_CHECK
/A PCRE_ANCHORED
/C PCRE_AUTO_CALLOUT
/E PCRE_DOLLAR_ENDONLY
/f PCRE_FIRSTLINE
/J PCRE_DUPNAMES
/N PCRE_NO_AUTO_CAPTURE
/U PCRE_UNGREEDY
/W PCRE_UCP
/X PCRE_EXTRA
/Y PCRE_NO_START_OPTIMIZE
/<JS> PCRE_JAVASCRIPT_COMPAT
/<cr> PCRE_NEWLINE_CR
/<lf> PCRE_NEWLINE_LF
/<crlf> PCRE_NEWLINE_CRLF
/<anycrlf> PCRE_NEWLINE_ANYCRLF
/<any> PCRE_NEWLINE_ANY
/<bsr_anycrlf> PCRE_BSR_ANYCRLF
/<bsr_unicode> PCRE_BSR_UNICODE
The modifiers that are enclosed in angle brackets are literal strings as shown,
including the angle brackets, but the letters can be in either case. This
example sets multiline matching with CRLF as the line ending sequence:
/^abc/m<crlf>
As well as turning on the PCRE_UTF8 option, the /8 modifier also causes
any non-printing characters in output strings to be printed using the
\ex{hh...} notation if they are valid UTF-8 sequences. Full details of the PCRE
options are given in the
HREF
pcreapi
documentation.
.
.
If any call to pcre_exec() in a /g or /G sequence matches an empty string, the next call is done with the PCRE_NOTEMPTY_ATSTART and PCRE_ANCHORED flags set in order to search for another, non-empty, match at the same point. If this second match fails, the start offset is advanced, and the normal match is retried. This imitates the way Perl handles such cases when using the /g modifier or the split() function. Normally, the start offset is advanced by one character, but if the newline convention recognizes CRLF as a newline, and the current character is CR followed by LF, an advance of two is used. . .
The /+ modifier requests that as well as outputting the substring that matched the entire pattern, pcretest should in addition output the remainder of the subject string. This is useful for tests where the subject contains multiple copies of the same substring.
The /B modifier is a debugging feature. It requests that pcretest output a representation of the compiled byte code after compilation. Normally this information contains length and offset values; however, if /Z is also present, this data is replaced by spaces. This is a special feature for use in the automatic test scripts; it ensures that the same output is generated for different internal link sizes.
The /D modifier is a PCRE debugging feature, and is equivalent to /BI, that is, both the /B and the /I modifiers.
The /F modifier causes pcretest to flip the byte order of the fields in the compiled pattern that contain 2-byte and 4-byte numbers. This facility is for testing the feature in PCRE that allows it to execute patterns that were compiled on a host with a different endianness. This feature is not available when the POSIX interface to PCRE is being used, that is, when the /P pattern modifier is specified. See also the section about saving and reloading compiled patterns below.
The /I modifier requests that pcretest output information about the compiled pattern (whether it is anchored, has a fixed first character, and so on). It does this by calling pcre_fullinfo() after compiling a pattern. If the pattern is studied, the results of that are also output.
The /K modifier requests pcretest to show names from backtracking control verbs that are returned from calls to pcre_exec(). It causes pcretest to create a pcre_extra block if one has not already been created by a call to pcre_study(), and to set the PCRE_EXTRA_MARK flag and the mark field within it, every time that pcre_exec() is called. If the variable that the mark field points to is non-NULL for a match, non-match, or partial match, pcretest prints the string to which it points. For a match, this is shown on a line by itself, tagged with "MK:". For a non-match it is added to the message.
The /L modifier must be followed directly by the name of a locale, for example, /pattern/Lfr_FR For this reason, it must be the last modifier. The given locale is set, pcre_maketables() is called to build a set of character tables for the locale, and this is then passed to pcre_compile() when compiling the regular expression. Without an /L (or /T) modifier, NULL is passed as the tables pointer; that is, /L applies only to the expression on which it appears.
The /M modifier causes the size of memory block used to hold the compiled pattern to be output.
The /S modifier causes pcre_study() to be called after the expression has been compiled, and the results used when the expression is matched.
The /T modifier must be followed by a single digit. It causes a specific set of built-in character tables to be passed to pcre_compile(). It is used in the standard PCRE tests to check behaviour with different character tables. The digit specifies the tables as follows: 0 the default ASCII tables, as distributed in pcre_chartables.c.dist 1 a set of tables defining ISO 8859 characters In table 1, some characters whose codes are greater than 128 are identified as letters, digits, spaces, etc. . .
\eqdd set the PCRE_MATCH_LIMIT limit to dd (any number of digits) \er carriage return (\ex0d) \et tab (\ex09) \ev vertical tab (\ex0b) \ennn octal character (up to 3 octal digits) always a byte unless > 255 in UTF-8 mode \exhh hexadecimal byte (up to 2 hex digits) JOIN
\ex{hh...} hexadecimal character, any number of digits in UTF-8 mode JOIN
\eA pass the PCRE_ANCHORED option to pcre_exec() or pcre_dfa_exec() JOIN
\eB pass the PCRE_NOTBOL option to pcre_exec() or pcre_dfa_exec() JOIN
\eCdd call pcre_copy_substring() for substring dd after a successful match (number less than 32) JOIN
\eCname call pcre_copy_named_substring() for substring "name" after a successful match (name termin- ated by next non alphanumeric character) JOIN
\eC+ show the current captured substrings at callout time \eC- do not supply a callout function JOIN
\eC!n return 1 instead of 0 when callout number n is reached JOIN
\eC!n!m return 1 instead of 0 when callout number n is reached for the nth time JOIN
\eC*n pass the number n (may be negative) as callout data; this is used as the callout return value \eD use the pcre_dfa_exec() match function \eF only shortest match for pcre_dfa_exec() JOIN
\eGdd call pcre_get_substring() for substring dd after a successful match (number less than 32) JOIN
\eGname call pcre_get_named_substring() for substring "name" after a successful match (name termin- ated by next non-alphanumeric character) JOIN
\eL call pcre_get_substringlist() after a successful match JOIN
\eM discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings JOIN
\eN pass the PCRE_NOTEMPTY option to pcre_exec() or pcre_dfa_exec(); if used twice, pass the PCRE_NOTEMPTY_ATSTART option JOIN
\eOdd set the size of the output vector passed to pcre_exec() to dd (any number of digits) JOIN
\eP pass the PCRE_PARTIAL_SOFT option to pcre_exec() or pcre_dfa_exec(); if used twice, pass the PCRE_PARTIAL_HARD option JOIN
\eQdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd (any number of digits) \eR pass the PCRE_DFA_RESTART option to pcre_dfa_exec() \eS output details of memory get/free calls during matching JOIN
\eY pass the PCRE_NO_START_OPTIMIZE option to pcre_exec() or pcre_dfa_exec() JOIN
\eZ pass the PCRE_NOTEOL option to pcre_exec() or pcre_dfa_exec() JOIN
\e? pass the PCRE_NO_UTF8_CHECK option to pcre_exec() or pcre_dfa_exec() JOIN
\e>dd start the match at offset dd (optional "-"; then any number of digits); this sets the startoffset argument for pcre_exec() or pcre_dfa_exec() JOIN
\e<cr> pass the PCRE_NEWLINE_CR option to pcre_exec() or pcre_dfa_exec() JOIN
\e<lf> pass the PCRE_NEWLINE_LF option to pcre_exec() or pcre_dfa_exec() JOIN
\e<crlf> pass the PCRE_NEWLINE_CRLF option to pcre_exec() or pcre_dfa_exec() JOIN
\e<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre_exec() or pcre_dfa_exec() JOIN
\e<any> pass the PCRE_NEWLINE_ANY option to pcre_exec() or pcre_dfa_exec() Note that \exhh always specifies one byte, even in UTF-8 mode; this makes it possible to construct invalid UTF-8 sequences for testing purposes. On the other hand, \ex{hh} is interpreted as a UTF-8 character in UTF-8 mode, generating more than one byte if the value is greater than 127. When not in UTF-8 mode, it generates one byte for values less than 256, and causes an error for greater values.
The escapes that specify line ending sequences are literal strings, exactly as shown. No more than one newline setting should be present in any data line.
A backslash followed by anything else just escapes the anything 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 \eM is present, pcretest calls pcre_exec() several times, with different values in the match_limit and match_limit_recursion fields of the pcre_extra data structure, until it finds the minimum numbers for each parameter that allow pcre_exec() to complete. The match_limit number is a measure of the amount of backtracking that takes place, and checking it out can be instructive. For most simple matches, the number is quite small, but for patterns with very large numbers of matching possibilities, it can become large very quickly with increasing length of subject string. The match_limit_recursion number is a measure of how much stack (or, if PCRE is compiled with NO_RECURSE, how much heap) memory is needed to complete the match attempt.
When \eO is used, the value specified may be higher or lower than the size set by the -O command line option (or defaulted to 45); \eO applies only to the call of pcre_exec() for the line in which it appears.
If the /P modifier was present on the pattern, causing the POSIX wrapper API to be used, the only option-setting sequences that have any effect are \eB, \eN, and \eZ, causing REG_NOTBOL, REG_NOTEMPTY, and REG_NOTEOL, respectively, to be passed to regexec().
The use of \ex{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 original UTF-8 rules of RFC 2279. This allows for values in the range 0 to 0x7FFFFFFF. Note that not all of those are valid Unicode code points, or indeed valid UTF-8 characters according to the later rules in RFC 3629. . .
pcrematching
documentation.
If a data line contains the \eD escape sequence, or if the command line contains the -dfa option, the alternative matching function is called. This function finds all possible matches at a given point. If, however, the \eF escape sequence is present in the data line, it stops after the first match is found. This is always the shortest possible match. . .
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. Otherwise, it outputs "No match" when the return is PCRE_ERROR_NOMATCH, and "Partial match:" followed by the partially matching substring when pcre_exec() returns PCRE_ERROR_PARTIAL. (Note that this is the entire substring that was inspected during the partial match; it may include characters before the actual match start if a lookbehind assertion, \eK, \eb, or \eB was involved.) For any other returns, it outputs the PCRE negative error number. Here is an example of an interactive pcretest run. $ pcretest PCRE version 7.0 30-Nov-2006 re> /^abc(\ed+)/ data> abc123 0: abc123 1: 123 data> xyz No match Note that unset capturing substrings that are not followed by one that is set are not returned by pcre_exec(), and are not shown by pcretest. In the following example, there are two capturing substrings, but when the first data line is matched, the second, unset substring is not shown. An "internal" unset substring is shown as "<unset>", as for the second data line. re> /(a)|(b)/ data> a 0: a 1: a data> b 0: b 1: <unset> 2: b If the strings contain any non-printing characters, they are output as \e0x escapes, or as \ex{...} escapes if the /8 modifier was present on the pattern. See below for the definition of non-printing characters. If the pattern has the /+ modifier, 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> /\eBi(\ew\ew)/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 \eC, \eG, or \eL 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 addition to the normal full list. The string length (that is, the return from the extraction function) is given in parentheses after each string for \eC and \eG.
Note that whereas 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 \en escape (or \er, \er\en, etc., depending on the newline sequence setting). . . .
If /g is present on the pattern, the search for further matches resumes at the end of the longest match. For example: re> /(tang|tangerine|tan)/g data> yellow tangerine and tangy sultana\eD 0: tangerine 1: tang 2: tan 0: tang 1: tan 0: tan Since the matching function does not support substring capture, the escape sequences that are concerned with captured substrings are not relevant. . .
pcrepartial
documentation. . .
Callouts numbered 255 are assumed to be automatic callouts, inserted as a result of the /C pattern modifier. In this case, instead of showing the callout number, the offset in the pattern, preceded by a plus, is output. For example: re> /\ed?[A-E]\e*/C data> E* --->E* +0 ^ \ed? +3 ^ [A-E] +8 ^^ \e* +10 ^ ^ 0: E* The callout function in pcretest returns zero (carry on matching) by default, but you can use a \eC item in a data line (as described above) to change this.
Inserting callouts can be helpful when using pcretest to check
complicated regular expressions. For further information about callouts, see
the
HREF
pcrecallout
documentation.
.
.
.
When pcretest is outputting text that is a matched part of a subject string, it behaves in the same way, unless a different locale has been set for the pattern (using the /L modifier). In this case, the isprint() function to distinguish printing and non-printing characters. . . .
When the POSIX interface is not in use, you can cause pcretest to write a
compiled pattern to a file, by following the modifiers with > and a file name.
For example:
/pattern/im >/some/file
See the
HREF
pcreprecompile
documentation for a discussion about saving and re-using compiled patterns.
The data that is written is binary. The first eight bytes are the length of the compiled pattern data followed by the length of the optional study data, each written as four bytes in big-endian order (most significant byte first). If there is no study data (either the pattern was not studied, or studying did not return any data), the second length is zero. The lengths are followed by an exact copy of the compiled pattern. If there is additional study data, this follows immediately after the compiled pattern. After writing the file, pcretest expects to read a new pattern.
A saved pattern can be reloaded into pcretest by specifing < and a file name instead of a pattern. The name of the file must not contain a < character, as otherwise pcretest will interpret the line as a pattern delimited by < characters. For example: re> </some/file Compiled regex loaded from /some/file No study data When the pattern has been loaded, pcretest proceeds to read data lines in the usual way.
You can copy a file written by pcretest to a different host and reload it there, even if the new host has opposite endianness to the one on which the pattern was compiled. For example, you can compile on an i86 machine and run on a SPARC machine.
File names for saving and reloading can be absolute or relative, but note that the shell facility of expanding a file name that starts with a tilde (~) is not available.
The ability to save and reload files in pcretest is intended for testing and experimentation. It is not intended for production use because only a single pattern can be written to a file. Furthermore, there is no facility for supplying custom character tables for use with a reloaded pattern. If the original pattern was compiled with custom tables, an attempt to match a subject string using a reloaded pattern is likely to cause pcretest to crash. Finally, if you attempt to load a file that is not in the correct format, the result is undefined. . .
Philip Hazel University Computing Service Cambridge CB2 3QH, England.. .
Last updated: 21 November 2010 Copyright (c) 1997-2010 University of Cambridge.