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<h1>pcresyntax man page</h1>
<p>
Return to the <a href="index.html">PCRE index page</a>.
</p>
<p>
This page is part of the PCRE HTML documentation. It was generated automatically
from the original man page. If there is any nonsense in it, please consult the
man page, in case the conversion went wrong.
<br>
<ul>
<li><a name="TOC1" href="#SEC1">PCRE REGULAR EXPRESSION SYNTAX SUMMARY</a>
<li><a name="TOC2" href="#SEC2">QUOTING</a>
<li><a name="TOC3" href="#SEC3">CHARACTERS</a>
<li><a name="TOC4" href="#SEC4">CHARACTER TYPES</a>
<li><a name="TOC5" href="#SEC5">GENERAL CATEGORY PROPERTIES FOR \p and \P</a>
<li><a name="TOC6" href="#SEC6">PCRE SPECIAL CATEGORY PROPERTIES FOR \p and \P</a>
<li><a name="TOC7" href="#SEC7">SCRIPT NAMES FOR \p AND \P</a>
<li><a name="TOC8" href="#SEC8">CHARACTER CLASSES</a>
<li><a name="TOC9" href="#SEC9">QUANTIFIERS</a>
<li><a name="TOC10" href="#SEC10">ANCHORS AND SIMPLE ASSERTIONS</a>
<li><a name="TOC11" href="#SEC11">MATCH POINT RESET</a>
<li><a name="TOC12" href="#SEC12">ALTERNATION</a>
<li><a name="TOC13" href="#SEC13">CAPTURING</a>
<li><a name="TOC14" href="#SEC14">ATOMIC GROUPS</a>
<li><a name="TOC15" href="#SEC15">COMMENT</a>
<li><a name="TOC16" href="#SEC16">OPTION SETTING</a>
<li><a name="TOC17" href="#SEC17">LOOKAHEAD AND LOOKBEHIND ASSERTIONS</a>
<li><a name="TOC18" href="#SEC18">BACKREFERENCES</a>
<li><a name="TOC19" href="#SEC19">SUBROUTINE REFERENCES (POSSIBLY RECURSIVE)</a>
<li><a name="TOC20" href="#SEC20">CONDITIONAL PATTERNS</a>
<li><a name="TOC21" href="#SEC21">BACKTRACKING CONTROL</a>
<li><a name="TOC22" href="#SEC22">NEWLINE CONVENTIONS</a>
<li><a name="TOC23" href="#SEC23">WHAT \R MATCHES</a>
<li><a name="TOC24" href="#SEC24">CALLOUTS</a>
<li><a name="TOC25" href="#SEC25">SEE ALSO</a>
<li><a name="TOC26" href="#SEC26">AUTHOR</a>
<li><a name="TOC27" href="#SEC27">REVISION</a>
</ul>
<br><a name="SEC1" href="#TOC1">PCRE REGULAR EXPRESSION SYNTAX SUMMARY</a><br>
<P>
The full syntax and semantics of the regular expressions that are supported by
PCRE are described in the
<a href="pcrepattern.html"><b>pcrepattern</b></a>
documentation. This document contains a quick-reference summary of the syntax.
</P>
<br><a name="SEC2" href="#TOC1">QUOTING</a><br>
<P>
<pre>
  \x         where x is non-alphanumeric is a literal x
  \Q...\E    treat enclosed characters as literal
</PRE>
</P>
<br><a name="SEC3" href="#TOC1">CHARACTERS</a><br>
<P>
<pre>
  \a         alarm, that is, the BEL character (hex 07)
  \cx        "control-x", where x is any ASCII character
  \e         escape (hex 1B)
  \f         form feed (hex 0C)
  \n         newline (hex 0A)
  \r         carriage return (hex 0D)
  \t         tab (hex 09)
  \0dd       character with octal code 0dd
  \ddd       character with octal code ddd, or backreference
  \o{ddd..}  character with octal code ddd..
  \xhh       character with hex code hh
  \x{hhh..}  character with hex code hhh..
</pre>
Note that \0dd is always an octal code, and that \8 and \9 are the literal
characters "8" and "9".
</P>
<br><a name="SEC4" href="#TOC1">CHARACTER TYPES</a><br>
<P>
<pre>
  .          any character except newline;
               in dotall mode, any character whatsoever
  \C         one data unit, even in UTF mode (best avoided)
  \d         a decimal digit
  \D         a character that is not a decimal digit
  \h         a horizontal white space character
  \H         a character that is not a horizontal white space character
  \N         a character that is not a newline
  \p{<i>xx</i>}     a character with the <i>xx</i> property
  \P{<i>xx</i>}     a character without the <i>xx</i> property
  \R         a newline sequence
  \s         a white space character
  \S         a character that is not a white space character
  \v         a vertical white space character
  \V         a character that is not a vertical white space character
  \w         a "word" character
  \W         a "non-word" character
  \X         a Unicode extended grapheme cluster
</pre>
By default, \d, \s, and \w match only ASCII characters, even in UTF-8 mode
or in the 16- bit and 32-bit libraries. However, if locale-specific matching is
happening, \s and \w may also match characters with code points in the range
128-255. If the PCRE_UCP option is set, the behaviour of these escape sequences
is changed to use Unicode properties and they match many more characters.
</P>
<br><a name="SEC5" href="#TOC1">GENERAL CATEGORY PROPERTIES FOR \p and \P</a><br>
<P>
<pre>
  C          Other
  Cc         Control
  Cf         Format
  Cn         Unassigned
  Co         Private use
  Cs         Surrogate

  L          Letter
  Ll         Lower case letter
  Lm         Modifier letter
  Lo         Other letter
  Lt         Title case letter
  Lu         Upper case letter
  L&         Ll, Lu, or Lt

  M          Mark
  Mc         Spacing mark
  Me         Enclosing mark
  Mn         Non-spacing mark

  N          Number
  Nd         Decimal number
  Nl         Letter number
  No         Other number

  P          Punctuation
  Pc         Connector punctuation
  Pd         Dash punctuation
  Pe         Close punctuation
  Pf         Final punctuation
  Pi         Initial punctuation
  Po         Other punctuation
  Ps         Open punctuation

  S          Symbol
  Sc         Currency symbol
  Sk         Modifier symbol
  Sm         Mathematical symbol
  So         Other symbol

  Z          Separator
  Zl         Line separator
  Zp         Paragraph separator
  Zs         Space separator
</PRE>
</P>
<br><a name="SEC6" href="#TOC1">PCRE SPECIAL CATEGORY PROPERTIES FOR \p and \P</a><br>
<P>
<pre>
  Xan        Alphanumeric: union of properties L and N
  Xps        POSIX space: property Z or tab, NL, VT, FF, CR
  Xsp        Perl space: property Z or tab, NL, VT, FF, CR
  Xuc        Univerally-named character: one that can be
               represented by a Universal Character Name
  Xwd        Perl word: property Xan or underscore
</pre>
Perl and POSIX space are now the same. Perl added VT to its space character set
at release 5.18 and PCRE changed at release 8.34.
</P>
<br><a name="SEC7" href="#TOC1">SCRIPT NAMES FOR \p AND \P</a><br>
<P>
Arabic,
Armenian,
Avestan,
Balinese,
Bamum,
Batak,
Bengali,
Bopomofo,
Brahmi,
Braille,
Buginese,
Buhid,
Canadian_Aboriginal,
Carian,
Chakma,
Cham,
Cherokee,
Common,
Coptic,
Cuneiform,
Cypriot,
Cyrillic,
Deseret,
Devanagari,
Egyptian_Hieroglyphs,
Ethiopic,
Georgian,
Glagolitic,
Gothic,
Greek,
Gujarati,
Gurmukhi,
Han,
Hangul,
Hanunoo,
Hebrew,
Hiragana,
Imperial_Aramaic,
Inherited,
Inscriptional_Pahlavi,
Inscriptional_Parthian,
Javanese,
Kaithi,
Kannada,
Katakana,
Kayah_Li,
Kharoshthi,
Khmer,
Lao,
Latin,
Lepcha,
Limbu,
Linear_B,
Lisu,
Lycian,
Lydian,
Malayalam,
Mandaic,
Meetei_Mayek,
Meroitic_Cursive,
Meroitic_Hieroglyphs,
Miao,
Mongolian,
Myanmar,
New_Tai_Lue,
Nko,
Ogham,
Old_Italic,
Old_Persian,
Old_South_Arabian,
Old_Turkic,
Ol_Chiki,
Oriya,
Osmanya,
Phags_Pa,
Phoenician,
Rejang,
Runic,
Samaritan,
Saurashtra,
Sharada,
Shavian,
Sinhala,
Sora_Sompeng,
Sundanese,
Syloti_Nagri,
Syriac,
Tagalog,
Tagbanwa,
Tai_Le,
Tai_Tham,
Tai_Viet,
Takri,
Tamil,
Telugu,
Thaana,
Thai,
Tibetan,
Tifinagh,
Ugaritic,
Vai,
Yi.
</P>
<br><a name="SEC8" href="#TOC1">CHARACTER CLASSES</a><br>
<P>
<pre>
  [...]       positive character class
  [^...]      negative character class
  [x-y]       range (can be used for hex characters)
  [[:xxx:]]   positive POSIX named set
  [[:^xxx:]]  negative POSIX named set

  alnum       alphanumeric
  alpha       alphabetic
  ascii       0-127
  blank       space or tab
  cntrl       control character
  digit       decimal digit
  graph       printing, excluding space
  lower       lower case letter
  print       printing, including space
  punct       printing, excluding alphanumeric
  space       white space
  upper       upper case letter
  word        same as \w
  xdigit      hexadecimal digit
</pre>
In PCRE, POSIX character set names recognize only ASCII characters by default,
but some of them use Unicode properties if PCRE_UCP is set. You can use
\Q...\E inside a character class.
</P>
<br><a name="SEC9" href="#TOC1">QUANTIFIERS</a><br>
<P>
<pre>
  ?           0 or 1, greedy
  ?+          0 or 1, possessive
  ??          0 or 1, lazy
  *           0 or more, greedy
  *+          0 or more, possessive
  *?          0 or more, lazy
  +           1 or more, greedy
  ++          1 or more, possessive
  +?          1 or more, lazy
  {n}         exactly n
  {n,m}       at least n, no more than m, greedy
  {n,m}+      at least n, no more than m, possessive
  {n,m}?      at least n, no more than m, lazy
  {n,}        n or more, greedy
  {n,}+       n or more, possessive
  {n,}?       n or more, lazy
</PRE>
</P>
<br><a name="SEC10" href="#TOC1">ANCHORS AND SIMPLE ASSERTIONS</a><br>
<P>
<pre>
  \b          word boundary
  \B          not a word boundary
  ^           start of subject
               also after internal newline in multiline mode
  \A          start of subject
  $           end of subject
               also before newline at end of subject
               also before internal newline in multiline mode
  \Z          end of subject
               also before newline at end of subject
  \z          end of subject
  \G          first matching position in subject
</PRE>
</P>
<br><a name="SEC11" href="#TOC1">MATCH POINT RESET</a><br>
<P>
<pre>
  \K          reset start of match
</PRE>
</P>
<br><a name="SEC12" href="#TOC1">ALTERNATION</a><br>
<P>
<pre>
  expr|expr|expr...
</PRE>
</P>
<br><a name="SEC13" href="#TOC1">CAPTURING</a><br>
<P>
<pre>
  (...)           capturing group
  (?&#60;name&#62;...)    named capturing group (Perl)
  (?'name'...)    named capturing group (Perl)
  (?P&#60;name&#62;...)   named capturing group (Python)
  (?:...)         non-capturing group
  (?|...)         non-capturing group; reset group numbers for
                   capturing groups in each alternative
</PRE>
</P>
<br><a name="SEC14" href="#TOC1">ATOMIC GROUPS</a><br>
<P>
<pre>
  (?&#62;...)         atomic, non-capturing group
</PRE>
</P>
<br><a name="SEC15" href="#TOC1">COMMENT</a><br>
<P>
<pre>
  (?#....)        comment (not nestable)
</PRE>
</P>
<br><a name="SEC16" href="#TOC1">OPTION SETTING</a><br>
<P>
<pre>
  (?i)            caseless
  (?J)            allow duplicate names
  (?m)            multiline
  (?s)            single line (dotall)
  (?U)            default ungreedy (lazy)
  (?x)            extended (ignore white space)
  (?-...)         unset option(s)
</pre>
The following are recognized only at the start of a pattern or after one of the
newline-setting options with similar syntax:
<pre>
  (*LIMIT_MATCH=d) set the match limit to d (decimal number)
  (*LIMIT_RECURSION=d) set the recursion limit to d (decimal number)
  (*NO_START_OPT) no start-match optimization (PCRE_NO_START_OPTIMIZE)
  (*UTF8)         set UTF-8 mode: 8-bit library (PCRE_UTF8)
  (*UTF16)        set UTF-16 mode: 16-bit library (PCRE_UTF16)
  (*UTF32)        set UTF-32 mode: 32-bit library (PCRE_UTF32)
  (*UTF)          set appropriate UTF mode for the library in use
  (*UCP)          set PCRE_UCP (use Unicode properties for \d etc)
</pre>
Note that LIMIT_MATCH and LIMIT_RECURSION can only reduce the value of the
limits set by the caller of pcre_exec(), not increase them.
</P>
<br><a name="SEC17" href="#TOC1">LOOKAHEAD AND LOOKBEHIND ASSERTIONS</a><br>
<P>
<pre>
  (?=...)         positive look ahead
  (?!...)         negative look ahead
  (?&#60;=...)        positive look behind
  (?&#60;!...)        negative look behind
</pre>
Each top-level branch of a look behind must be of a fixed length.
</P>
<br><a name="SEC18" href="#TOC1">BACKREFERENCES</a><br>
<P>
<pre>
  \n              reference by number (can be ambiguous)
  \gn             reference by number
  \g{n}           reference by number
  \g{-n}          relative reference by number
  \k&#60;name&#62;        reference by name (Perl)
  \k'name'        reference by name (Perl)
  \g{name}        reference by name (Perl)
  \k{name}        reference by name (.NET)
  (?P=name)       reference by name (Python)
</PRE>
</P>
<br><a name="SEC19" href="#TOC1">SUBROUTINE REFERENCES (POSSIBLY RECURSIVE)</a><br>
<P>
<pre>
  (?R)            recurse whole pattern
  (?n)            call subpattern by absolute number
  (?+n)           call subpattern by relative number
  (?-n)           call subpattern by relative number
  (?&name)        call subpattern by name (Perl)
  (?P&#62;name)       call subpattern by name (Python)
  \g&#60;name&#62;        call subpattern by name (Oniguruma)
  \g'name'        call subpattern by name (Oniguruma)
  \g&#60;n&#62;           call subpattern by absolute number (Oniguruma)
  \g'n'           call subpattern by absolute number (Oniguruma)
  \g&#60;+n&#62;          call subpattern by relative number (PCRE extension)
  \g'+n'          call subpattern by relative number (PCRE extension)
  \g&#60;-n&#62;          call subpattern by relative number (PCRE extension)
  \g'-n'          call subpattern by relative number (PCRE extension)
</PRE>
</P>
<br><a name="SEC20" href="#TOC1">CONDITIONAL PATTERNS</a><br>
<P>
<pre>
  (?(condition)yes-pattern)
  (?(condition)yes-pattern|no-pattern)

  (?(n)...        absolute reference condition
  (?(+n)...       relative reference condition
  (?(-n)...       relative reference condition
  (?(&#60;name&#62;)...   named reference condition (Perl)
  (?('name')...   named reference condition (Perl)
  (?(name)...     named reference condition (PCRE)
  (?(R)...        overall recursion condition
  (?(Rn)...       specific group recursion condition
  (?(R&name)...   specific recursion condition
  (?(DEFINE)...   define subpattern for reference
  (?(assert)...   assertion condition
</PRE>
</P>
<br><a name="SEC21" href="#TOC1">BACKTRACKING CONTROL</a><br>
<P>
The following act immediately they are reached:
<pre>
  (*ACCEPT)       force successful match
  (*FAIL)         force backtrack; synonym (*F)
  (*MARK:NAME)    set name to be passed back; synonym (*:NAME)
</pre>
The following act only when a subsequent match failure causes a backtrack to
reach them. They all force a match failure, but they differ in what happens
afterwards. Those that advance the start-of-match point do so only if the
pattern is not anchored.
<pre>
  (*COMMIT)       overall failure, no advance of starting point
  (*PRUNE)        advance to next starting character
  (*PRUNE:NAME)   equivalent to (*MARK:NAME)(*PRUNE)
  (*SKIP)         advance to current matching position
  (*SKIP:NAME)    advance to position corresponding to an earlier
                  (*MARK:NAME); if not found, the (*SKIP) is ignored
  (*THEN)         local failure, backtrack to next alternation
  (*THEN:NAME)    equivalent to (*MARK:NAME)(*THEN)
</PRE>
</P>
<br><a name="SEC22" href="#TOC1">NEWLINE CONVENTIONS</a><br>
<P>
These are recognized only at the very start of the pattern or after a
(*BSR_...), (*UTF8), (*UTF16), (*UTF32) or (*UCP) option.
<pre>
  (*CR)           carriage return only
  (*LF)           linefeed only
  (*CRLF)         carriage return followed by linefeed
  (*ANYCRLF)      all three of the above
  (*ANY)          any Unicode newline sequence
</PRE>
</P>
<br><a name="SEC23" href="#TOC1">WHAT \R MATCHES</a><br>
<P>
These are recognized only at the very start of the pattern or after a
(*...) option that sets the newline convention or a UTF or UCP mode.
<pre>
  (*BSR_ANYCRLF)  CR, LF, or CRLF
  (*BSR_UNICODE)  any Unicode newline sequence
</PRE>
</P>
<br><a name="SEC24" href="#TOC1">CALLOUTS</a><br>
<P>
<pre>
  (?C)      callout
  (?Cn)     callout with data n
</PRE>
</P>
<br><a name="SEC25" href="#TOC1">SEE ALSO</a><br>
<P>
<b>pcrepattern</b>(3), <b>pcreapi</b>(3), <b>pcrecallout</b>(3),
<b>pcrematching</b>(3), <b>pcre</b>(3).
</P>
<br><a name="SEC26" href="#TOC1">AUTHOR</a><br>
<P>
Philip Hazel
<br>
University Computing Service
<br>
Cambridge CB2 3QH, England.
<br>
</P>
<br><a name="SEC27" href="#TOC1">REVISION</a><br>
<P>
Last updated: 12 November 2013
<br>
Copyright &copy; 1997-2013 University of Cambridge.
<br>
<p>
Return to the <a href="index.html">PCRE index page</a>.
</p>
1	<html>
2	<head>
3	<title>pcresyntax specification</title>
4	</head>
5	<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB">
6	<h1>pcresyntax man page</h1>
7	<p>
8	Return to the <a href="index.html">PCRE index page</a>.
9	</p>
10	<p>
11	This page is part of the PCRE HTML documentation. It was generated automatically
12	from the original man page. If there is any nonsense in it, please consult the
13	man page, in case the conversion went wrong.
14	<br>
15	<ul>
16	<li><a name="TOC1" href="#SEC1">PCRE REGULAR EXPRESSION SYNTAX SUMMARY</a>
17	<li><a name="TOC2" href="#SEC2">QUOTING</a>
18	<li><a name="TOC3" href="#SEC3">CHARACTERS</a>
19	<li><a name="TOC4" href="#SEC4">CHARACTER TYPES</a>
20	<li><a name="TOC5" href="#SEC5">GENERAL CATEGORY PROPERTIES FOR \p and \P</a>
21	<li><a name="TOC6" href="#SEC6">PCRE SPECIAL CATEGORY PROPERTIES FOR \p and \P</a>
22	<li><a name="TOC7" href="#SEC7">SCRIPT NAMES FOR \p AND \P</a>
23	<li><a name="TOC8" href="#SEC8">CHARACTER CLASSES</a>
24	<li><a name="TOC9" href="#SEC9">QUANTIFIERS</a>
25	<li><a name="TOC10" href="#SEC10">ANCHORS AND SIMPLE ASSERTIONS</a>
26	<li><a name="TOC11" href="#SEC11">MATCH POINT RESET</a>
27	<li><a name="TOC12" href="#SEC12">ALTERNATION</a>
28	<li><a name="TOC13" href="#SEC13">CAPTURING</a>
29	<li><a name="TOC14" href="#SEC14">ATOMIC GROUPS</a>
30	<li><a name="TOC15" href="#SEC15">COMMENT</a>
31	<li><a name="TOC16" href="#SEC16">OPTION SETTING</a>
32	<li><a name="TOC17" href="#SEC17">LOOKAHEAD AND LOOKBEHIND ASSERTIONS</a>
33	<li><a name="TOC18" href="#SEC18">BACKREFERENCES</a>
34	<li><a name="TOC19" href="#SEC19">SUBROUTINE REFERENCES (POSSIBLY RECURSIVE)</a>
35	<li><a name="TOC20" href="#SEC20">CONDITIONAL PATTERNS</a>
36	<li><a name="TOC21" href="#SEC21">BACKTRACKING CONTROL</a>
37	<li><a name="TOC22" href="#SEC22">NEWLINE CONVENTIONS</a>
38	<li><a name="TOC23" href="#SEC23">WHAT \R MATCHES</a>
39	<li><a name="TOC24" href="#SEC24">CALLOUTS</a>
40	<li><a name="TOC25" href="#SEC25">SEE ALSO</a>
41	<li><a name="TOC26" href="#SEC26">AUTHOR</a>
42	<li><a name="TOC27" href="#SEC27">REVISION</a>
43	</ul>
44	<br><a name="SEC1" href="#TOC1">PCRE REGULAR EXPRESSION SYNTAX SUMMARY</a><br>
45	<P>
46	The full syntax and semantics of the regular expressions that are supported by
47	PCRE are described in the
48	<a href="pcrepattern.html"><b>pcrepattern</b></a>
49	documentation. This document contains a quick-reference summary of the syntax.
50	</P>
51	<br><a name="SEC2" href="#TOC1">QUOTING</a><br>
52	<P>
53	<pre>
54	\x where x is non-alphanumeric is a literal x
55	\Q...\E treat enclosed characters as literal
56	</PRE>
57	</P>
58	<br><a name="SEC3" href="#TOC1">CHARACTERS</a><br>
59	<P>
60	<pre>
61	\a alarm, that is, the BEL character (hex 07)
62	\cx "control-x", where x is any ASCII character
63	\e escape (hex 1B)
64	\f form feed (hex 0C)
65	\n newline (hex 0A)
66	\r carriage return (hex 0D)
67	\t tab (hex 09)
68	\0dd character with octal code 0dd
69	\ddd character with octal code ddd, or backreference
70	\o{ddd..} character with octal code ddd..
71	\xhh character with hex code hh
72	\x{hhh..} character with hex code hhh..
73	</pre>
74	Note that \0dd is always an octal code, and that \8 and \9 are the literal
75	characters "8" and "9".
76	</P>
77	<br><a name="SEC4" href="#TOC1">CHARACTER TYPES</a><br>
78	<P>
79	<pre>
80	. any character except newline;
81	in dotall mode, any character whatsoever
82	\C one data unit, even in UTF mode (best avoided)
83	\d a decimal digit
84	\D a character that is not a decimal digit
85	\h a horizontal white space character
86	\H a character that is not a horizontal white space character
87	\N a character that is not a newline
88	\p{<i>xx</i>} a character with the <i>xx</i> property
89	\P{<i>xx</i>} a character without the <i>xx</i> property
90	\R a newline sequence
91	\s a white space character
92	\S a character that is not a white space character
93	\v a vertical white space character
94	\V a character that is not a vertical white space character
95	\w a "word" character
96	\W a "non-word" character
97	\X a Unicode extended grapheme cluster
98	</pre>
99	By default, \d, \s, and \w match only ASCII characters, even in UTF-8 mode
100	or in the 16- bit and 32-bit libraries. However, if locale-specific matching is
101	happening, \s and \w may also match characters with code points in the range
102	128-255. If the PCRE_UCP option is set, the behaviour of these escape sequences
103	is changed to use Unicode properties and they match many more characters.
104	</P>
105	<br><a name="SEC5" href="#TOC1">GENERAL CATEGORY PROPERTIES FOR \p and \P</a><br>
106	<P>
107	<pre>
108	C Other
109	Cc Control
110	Cf Format
111	Cn Unassigned
112	Co Private use
113	Cs Surrogate
114
115	L Letter
116	Ll Lower case letter
117	Lm Modifier letter
118	Lo Other letter
119	Lt Title case letter
120	Lu Upper case letter
121	L& Ll, Lu, or Lt
122
123	M Mark
124	Mc Spacing mark
125	Me Enclosing mark
126	Mn Non-spacing mark
127
128	N Number
129	Nd Decimal number
130	Nl Letter number
131	No Other number
132
133	P Punctuation
134	Pc Connector punctuation
135	Pd Dash punctuation
136	Pe Close punctuation
137	Pf Final punctuation
138	Pi Initial punctuation
139	Po Other punctuation
140	Ps Open punctuation
141
142	S Symbol
143	Sc Currency symbol
144	Sk Modifier symbol
145	Sm Mathematical symbol
146	So Other symbol
147
148	Z Separator
149	Zl Line separator
150	Zp Paragraph separator
151	Zs Space separator
152	</PRE>
153	</P>
154	<br><a name="SEC6" href="#TOC1">PCRE SPECIAL CATEGORY PROPERTIES FOR \p and \P</a><br>
155	<P>
156	<pre>
157	Xan Alphanumeric: union of properties L and N
158	Xps POSIX space: property Z or tab, NL, VT, FF, CR
159	Xsp Perl space: property Z or tab, NL, VT, FF, CR
160	Xuc Univerally-named character: one that can be
161	represented by a Universal Character Name
162	Xwd Perl word: property Xan or underscore
163	</pre>
164	Perl and POSIX space are now the same. Perl added VT to its space character set
165	at release 5.18 and PCRE changed at release 8.34.
166	</P>
167	<br><a name="SEC7" href="#TOC1">SCRIPT NAMES FOR \p AND \P</a><br>
168	<P>
169	Arabic,
170	Armenian,
171	Avestan,
172	Balinese,
173	Bamum,
174	Batak,
175	Bengali,
176	Bopomofo,
177	Brahmi,
178	Braille,
179	Buginese,
180	Buhid,
181	Canadian_Aboriginal,
182	Carian,
183	Chakma,
184	Cham,
185	Cherokee,
186	Common,
187	Coptic,
188	Cuneiform,
189	Cypriot,
190	Cyrillic,
191	Deseret,
192	Devanagari,
193	Egyptian_Hieroglyphs,
194	Ethiopic,
195	Georgian,
196	Glagolitic,
197	Gothic,
198	Greek,
199	Gujarati,
200	Gurmukhi,
201	Han,
202	Hangul,
203	Hanunoo,
204	Hebrew,
205	Hiragana,
206	Imperial_Aramaic,
207	Inherited,
208	Inscriptional_Pahlavi,
209	Inscriptional_Parthian,
210	Javanese,
211	Kaithi,
212	Kannada,
213	Katakana,
214	Kayah_Li,
215	Kharoshthi,
216	Khmer,
217	Lao,
218	Latin,
219	Lepcha,
220	Limbu,
221	Linear_B,
222	Lisu,
223	Lycian,
224	Lydian,
225	Malayalam,
226	Mandaic,
227	Meetei_Mayek,
228	Meroitic_Cursive,
229	Meroitic_Hieroglyphs,
230	Miao,
231	Mongolian,
232	Myanmar,
233	New_Tai_Lue,
234	Nko,
235	Ogham,
236	Old_Italic,
237	Old_Persian,
238	Old_South_Arabian,
239	Old_Turkic,
240	Ol_Chiki,
241	Oriya,
242	Osmanya,
243	Phags_Pa,
244	Phoenician,
245	Rejang,
246	Runic,
247	Samaritan,
248	Saurashtra,
249	Sharada,
250	Shavian,
251	Sinhala,
252	Sora_Sompeng,
253	Sundanese,
254	Syloti_Nagri,
255	Syriac,
256	Tagalog,
257	Tagbanwa,
258	Tai_Le,
259	Tai_Tham,
260	Tai_Viet,
261	Takri,
262	Tamil,
263	Telugu,
264	Thaana,
265	Thai,
266	Tibetan,
267	Tifinagh,
268	Ugaritic,
269	Vai,
270	Yi.
271	</P>
272	<br><a name="SEC8" href="#TOC1">CHARACTER CLASSES</a><br>
273	<P>
274	<pre>
275	[...] positive character class
276	[^...] negative character class
277	[x-y] range (can be used for hex characters)
278	[[:xxx:]] positive POSIX named set
279	[[:^xxx:]] negative POSIX named set
280
281	alnum alphanumeric
282	alpha alphabetic
283	ascii 0-127
284	blank space or tab
285	cntrl control character
286	digit decimal digit
287	graph printing, excluding space
288	lower lower case letter
289	print printing, including space
290	punct printing, excluding alphanumeric
291	space white space
292	upper upper case letter
293	word same as \w
294	xdigit hexadecimal digit
295	</pre>
296	In PCRE, POSIX character set names recognize only ASCII characters by default,
297	but some of them use Unicode properties if PCRE_UCP is set. You can use
298	\Q...\E inside a character class.
299	</P>
300	<br><a name="SEC9" href="#TOC1">QUANTIFIERS</a><br>
301	<P>
302	<pre>
303	? 0 or 1, greedy
304	?+ 0 or 1, possessive
305	?? 0 or 1, lazy
306	* 0 or more, greedy
307	*+ 0 or more, possessive
308	*? 0 or more, lazy
309	+ 1 or more, greedy
310	++ 1 or more, possessive
311	+? 1 or more, lazy
312	{n} exactly n
313	{n,m} at least n, no more than m, greedy
314	{n,m}+ at least n, no more than m, possessive
315	{n,m}? at least n, no more than m, lazy
316	{n,} n or more, greedy
317	{n,}+ n or more, possessive
318	{n,}? n or more, lazy
319	</PRE>
320	</P>
321	<br><a name="SEC10" href="#TOC1">ANCHORS AND SIMPLE ASSERTIONS</a><br>
322	<P>
323	<pre>
324	\b word boundary
325	\B not a word boundary
326	^ start of subject
327	also after internal newline in multiline mode
328	\A start of subject
329	$ end of subject
330	also before newline at end of subject
331	also before internal newline in multiline mode
332	\Z end of subject
333	also before newline at end of subject
334	\z end of subject
335	\G first matching position in subject
336	</PRE>
337	</P>
338	<br><a name="SEC11" href="#TOC1">MATCH POINT RESET</a><br>
339	<P>
340	<pre>
341	\K reset start of match
342	</PRE>
343	</P>
344	<br><a name="SEC12" href="#TOC1">ALTERNATION</a><br>
345	<P>
346	<pre>
347	expr\|expr\|expr...
348	</PRE>
349	</P>
350	<br><a name="SEC13" href="#TOC1">CAPTURING</a><br>
351	<P>
352	<pre>
353	(...) capturing group
354	(?<name>...) named capturing group (Perl)
355	(?'name'...) named capturing group (Perl)
356	(?P<name>...) named capturing group (Python)
357	(?:...) non-capturing group
358	(?\|...) non-capturing group; reset group numbers for
359	capturing groups in each alternative
360	</PRE>
361	</P>
362	<br><a name="SEC14" href="#TOC1">ATOMIC GROUPS</a><br>
363	<P>
364	<pre>
365	(?>...) atomic, non-capturing group
366	</PRE>
367	</P>
368	<br><a name="SEC15" href="#TOC1">COMMENT</a><br>
369	<P>
370	<pre>
371	(?#....) comment (not nestable)
372	</PRE>
373	</P>
374	<br><a name="SEC16" href="#TOC1">OPTION SETTING</a><br>
375	<P>
376	<pre>
377	(?i) caseless
378	(?J) allow duplicate names
379	(?m) multiline
380	(?s) single line (dotall)
381	(?U) default ungreedy (lazy)
382	(?x) extended (ignore white space)
383	(?-...) unset option(s)
384	</pre>
385	The following are recognized only at the start of a pattern or after one of the
386	newline-setting options with similar syntax:
387	<pre>
388	(*LIMIT_MATCH=d) set the match limit to d (decimal number)
389	(*LIMIT_RECURSION=d) set the recursion limit to d (decimal number)
390	(*NO_START_OPT) no start-match optimization (PCRE_NO_START_OPTIMIZE)
391	(*UTF8) set UTF-8 mode: 8-bit library (PCRE_UTF8)
392	(*UTF16) set UTF-16 mode: 16-bit library (PCRE_UTF16)
393	(*UTF32) set UTF-32 mode: 32-bit library (PCRE_UTF32)
394	(*UTF) set appropriate UTF mode for the library in use
395	(*UCP) set PCRE_UCP (use Unicode properties for \d etc)
396	</pre>
397	Note that LIMIT_MATCH and LIMIT_RECURSION can only reduce the value of the
398	limits set by the caller of pcre_exec(), not increase them.
399	</P>
400	<br><a name="SEC17" href="#TOC1">LOOKAHEAD AND LOOKBEHIND ASSERTIONS</a><br>
401	<P>
402	<pre>
403	(?=...) positive look ahead
404	(?!...) negative look ahead
405	(?<=...) positive look behind
406	(?<!...) negative look behind
407	</pre>
408	Each top-level branch of a look behind must be of a fixed length.
409	</P>
410	<br><a name="SEC18" href="#TOC1">BACKREFERENCES</a><br>
411	<P>
412	<pre>
413	\n reference by number (can be ambiguous)
414	\gn reference by number
415	\g{n} reference by number
416	\g{-n} relative reference by number
417	\k<name> reference by name (Perl)
418	\k'name' reference by name (Perl)
419	\g{name} reference by name (Perl)
420	\k{name} reference by name (.NET)
421	(?P=name) reference by name (Python)
422	</PRE>
423	</P>
424	<br><a name="SEC19" href="#TOC1">SUBROUTINE REFERENCES (POSSIBLY RECURSIVE)</a><br>
425	<P>
426	<pre>
427	(?R) recurse whole pattern
428	(?n) call subpattern by absolute number
429	(?+n) call subpattern by relative number
430	(?-n) call subpattern by relative number
431	(?&name) call subpattern by name (Perl)
432	(?P>name) call subpattern by name (Python)
433	\g<name> call subpattern by name (Oniguruma)
434	\g'name' call subpattern by name (Oniguruma)
435	\g<n> call subpattern by absolute number (Oniguruma)
436	\g'n' call subpattern by absolute number (Oniguruma)
437	\g<+n> call subpattern by relative number (PCRE extension)
438	\g'+n' call subpattern by relative number (PCRE extension)
439	\g<-n> call subpattern by relative number (PCRE extension)
440	\g'-n' call subpattern by relative number (PCRE extension)
441	</PRE>
442	</P>
443	<br><a name="SEC20" href="#TOC1">CONDITIONAL PATTERNS</a><br>
444	<P>
445	<pre>
446	(?(condition)yes-pattern)
447	(?(condition)yes-pattern\|no-pattern)
448
449	(?(n)... absolute reference condition
450	(?(+n)... relative reference condition
451	(?(-n)... relative reference condition
452	(?(<name>)... named reference condition (Perl)
453	(?('name')... named reference condition (Perl)
454	(?(name)... named reference condition (PCRE)
455	(?(R)... overall recursion condition
456	(?(Rn)... specific group recursion condition
457	(?(R&name)... specific recursion condition
458	(?(DEFINE)... define subpattern for reference
459	(?(assert)... assertion condition
460	</PRE>
461	</P>
462	<br><a name="SEC21" href="#TOC1">BACKTRACKING CONTROL</a><br>
463	<P>
464	The following act immediately they are reached:
465	<pre>
466	(*ACCEPT) force successful match
467	(FAIL) force backtrack; synonym (F)
468	(MARK:NAME) set name to be passed back; synonym (:NAME)
469	</pre>
470	The following act only when a subsequent match failure causes a backtrack to
471	reach them. They all force a match failure, but they differ in what happens
472	afterwards. Those that advance the start-of-match point do so only if the
473	pattern is not anchored.
474	<pre>
475	(*COMMIT) overall failure, no advance of starting point
476	(*PRUNE) advance to next starting character
477	(PRUNE:NAME) equivalent to (MARK:NAME)(*PRUNE)
478	(*SKIP) advance to current matching position
479	(*SKIP:NAME) advance to position corresponding to an earlier
480	(MARK:NAME); if not found, the (SKIP) is ignored
481	(*THEN) local failure, backtrack to next alternation
482	(THEN:NAME) equivalent to (MARK:NAME)(*THEN)
483	</PRE>
484	</P>
485	<br><a name="SEC22" href="#TOC1">NEWLINE CONVENTIONS</a><br>
486	<P>
487	These are recognized only at the very start of the pattern or after a
488	(BSR_...), (UTF8), (UTF16), (UTF32) or (*UCP) option.
489	<pre>
490	(*CR) carriage return only
491	(*LF) linefeed only
492	(*CRLF) carriage return followed by linefeed
493	(*ANYCRLF) all three of the above
494	(*ANY) any Unicode newline sequence
495	</PRE>
496	</P>
497	<br><a name="SEC23" href="#TOC1">WHAT \R MATCHES</a><br>
498	<P>
499	These are recognized only at the very start of the pattern or after a
500	(*...) option that sets the newline convention or a UTF or UCP mode.
501	<pre>
502	(*BSR_ANYCRLF) CR, LF, or CRLF
503	(*BSR_UNICODE) any Unicode newline sequence
504	</PRE>
505	</P>
506	<br><a name="SEC24" href="#TOC1">CALLOUTS</a><br>
507	<P>
508	<pre>
509	(?C) callout
510	(?Cn) callout with data n
511	</PRE>
512	</P>
513	<br><a name="SEC25" href="#TOC1">SEE ALSO</a><br>
514	<P>
515	<b>pcrepattern</b>(3), <b>pcreapi</b>(3), <b>pcrecallout</b>(3),
516	<b>pcrematching</b>(3), <b>pcre</b>(3).
517	</P>
518	<br><a name="SEC26" href="#TOC1">AUTHOR</a><br>
519	<P>
520	Philip Hazel
521	<br>
522	University Computing Service
523	<br>
524	Cambridge CB2 3QH, England.
525	<br>
526	</P>
527	<br><a name="SEC27" href="#TOC1">REVISION</a><br>
528	<P>
529	Last updated: 12 November 2013
530	<br>
531	Copyright © 1997-2013 University of Cambridge.
532	<br>
533	<p>
534	Return to the <a href="index.html">PCRE index page</a>.
535	</p>