| .TH PCRESYNTAX 3 |
| .SH NAME |
| PCRE - Perl-compatible regular expressions |
| .SH "PCRE REGULAR EXPRESSION SYNTAX SUMMARY" |
| .rs |
| .sp |
| The full syntax and semantics of the regular expressions that are supported by |
| PCRE are described in the |
| .\" HREF |
| \fBpcrepattern\fP |
| .\" |
| documentation. This document contains just a quick-reference summary of the |
| syntax. |
| . |
| . |
| .SH "QUOTING" |
| .rs |
| .sp |
| \ex where x is non-alphanumeric is a literal x |
| \eQ...\eE treat enclosed characters as literal |
| . |
| . |
| .SH "CHARACTERS" |
| .rs |
| .sp |
| \ea alarm, that is, the BEL character (hex 07) |
| \ecx "control-x", where x is any ASCII character |
| \ee escape (hex 1B) |
| \ef formfeed (hex 0C) |
| \en newline (hex 0A) |
| \er carriage return (hex 0D) |
| \et tab (hex 09) |
| \eddd character with octal code ddd, or backreference |
| \exhh character with hex code hh |
| \ex{hhh..} character with hex code hhh.. |
| . |
| . |
| .SH "CHARACTER TYPES" |
| .rs |
| .sp |
| . any character except newline; |
| in dotall mode, any character whatsoever |
| \eC one byte, even in UTF-8 mode (best avoided) |
| \ed a decimal digit |
| \eD a character that is not a decimal digit |
| \eh a horizontal whitespace character |
| \eH a character that is not a horizontal whitespace character |
| \eN a character that is not a newline |
| \ep{\fIxx\fP} a character with the \fIxx\fP property |
| \eP{\fIxx\fP} a character without the \fIxx\fP property |
| \eR a newline sequence |
| \es a whitespace character |
| \eS a character that is not a whitespace character |
| \ev a vertical whitespace character |
| \eV a character that is not a vertical whitespace character |
| \ew a "word" character |
| \eW a "non-word" character |
| \eX an extended Unicode sequence |
| .sp |
| In PCRE, by default, \ed, \eD, \es, \eS, \ew, and \eW recognize only ASCII |
| characters, even in UTF-8 mode. However, this can be changed by setting the |
| PCRE_UCP option. |
| . |
| . |
| .SH "GENERAL CATEGORY PROPERTIES FOR \ep and \eP" |
| .rs |
| .sp |
| C Other |
| Cc Control |
| Cf Format |
| Cn Unassigned |
| Co Private use |
| Cs Surrogate |
| .sp |
| 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 |
| .sp |
| M Mark |
| Mc Spacing mark |
| Me Enclosing mark |
| Mn Non-spacing mark |
| .sp |
| N Number |
| Nd Decimal number |
| Nl Letter number |
| No Other number |
| .sp |
| P Punctuation |
| Pc Connector punctuation |
| Pd Dash punctuation |
| Pe Close punctuation |
| Pf Final punctuation |
| Pi Initial punctuation |
| Po Other punctuation |
| Ps Open punctuation |
| .sp |
| S Symbol |
| Sc Currency symbol |
| Sk Modifier symbol |
| Sm Mathematical symbol |
| So Other symbol |
| .sp |
| Z Separator |
| Zl Line separator |
| Zp Paragraph separator |
| Zs Space separator |
| . |
| . |
| .SH "PCRE SPECIAL CATEGORY PROPERTIES FOR \ep and \eP" |
| .rs |
| .sp |
| 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, FF, CR |
| Xwd Perl word: property Xan or underscore |
| . |
| . |
| .SH "SCRIPT NAMES FOR \ep AND \eP" |
| .rs |
| .sp |
| Arabic, |
| Armenian, |
| Avestan, |
| Balinese, |
| Bamum, |
| Bengali, |
| Bopomofo, |
| Braille, |
| Buginese, |
| Buhid, |
| Canadian_Aboriginal, |
| Carian, |
| 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, |
| Meetei_Mayek, |
| 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, |
| Shavian, |
| Sinhala, |
| Sundanese, |
| Syloti_Nagri, |
| Syriac, |
| Tagalog, |
| Tagbanwa, |
| Tai_Le, |
| Tai_Tham, |
| Tai_Viet, |
| Tamil, |
| Telugu, |
| Thaana, |
| Thai, |
| Tibetan, |
| Tifinagh, |
| Ugaritic, |
| Vai, |
| Yi. |
| . |
| . |
| .SH "CHARACTER CLASSES" |
| .rs |
| .sp |
| [...] 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 |
| .sp |
| 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 whitespace |
| upper upper case letter |
| word same as \ew |
| xdigit hexadecimal digit |
| .sp |
| 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 |
| \eQ...\eE inside a character class. |
| . |
| . |
| .SH "QUANTIFIERS" |
| .rs |
| .sp |
| ? 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 |
| . |
| . |
| .SH "ANCHORS AND SIMPLE ASSERTIONS" |
| .rs |
| .sp |
| \eb word boundary |
| \eB not a word boundary |
| ^ start of subject |
| also after internal newline in multiline mode |
| \eA start of subject |
| $ end of subject |
| also before newline at end of subject |
| also before internal newline in multiline mode |
| \eZ end of subject |
| also before newline at end of subject |
| \ez end of subject |
| \eG first matching position in subject |
| . |
| . |
| .SH "MATCH POINT RESET" |
| .rs |
| .sp |
| \eK reset start of match |
| . |
| . |
| .SH "ALTERNATION" |
| .rs |
| .sp |
| expr|expr|expr... |
| . |
| . |
| .SH "CAPTURING" |
| .rs |
| .sp |
| (...) capturing group |
| (?<name>...) named capturing group (Perl) |
| (?'name'...) named capturing group (Perl) |
| (?P<name>...) named capturing group (Python) |
| (?:...) non-capturing group |
| (?|...) non-capturing group; reset group numbers for |
| capturing groups in each alternative |
| . |
| . |
| .SH "ATOMIC GROUPS" |
| .rs |
| .sp |
| (?>...) atomic, non-capturing group |
| . |
| . |
| . |
| . |
| .SH "COMMENT" |
| .rs |
| .sp |
| (?#....) comment (not nestable) |
| . |
| . |
| .SH "OPTION SETTING" |
| .rs |
| .sp |
| (?i) caseless |
| (?J) allow duplicate names |
| (?m) multiline |
| (?s) single line (dotall) |
| (?U) default ungreedy (lazy) |
| (?x) extended (ignore white space) |
| (?-...) unset option(s) |
| .sp |
| The following are recognized only at the start of a pattern or after one of the |
| newline-setting options with similar syntax: |
| .sp |
| (*NO_START_OPT) no start-match optimization (PCRE_NO_START_OPTIMIZE) |
| (*UTF8) set UTF-8 mode (PCRE_UTF8) |
| (*UCP) set PCRE_UCP (use Unicode properties for \ed etc) |
| . |
| . |
| .SH "LOOKAHEAD AND LOOKBEHIND ASSERTIONS" |
| .rs |
| .sp |
| (?=...) positive look ahead |
| (?!...) negative look ahead |
| (?<=...) positive look behind |
| (?<!...) negative look behind |
| .sp |
| Each top-level branch of a look behind must be of a fixed length. |
| . |
| . |
| .SH "BACKREFERENCES" |
| .rs |
| .sp |
| \en reference by number (can be ambiguous) |
| \egn reference by number |
| \eg{n} reference by number |
| \eg{-n} relative reference by number |
| \ek<name> reference by name (Perl) |
| \ek'name' reference by name (Perl) |
| \eg{name} reference by name (Perl) |
| \ek{name} reference by name (.NET) |
| (?P=name) reference by name (Python) |
| . |
| . |
| .SH "SUBROUTINE REFERENCES (POSSIBLY RECURSIVE)" |
| .rs |
| .sp |
| (?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>name) call subpattern by name (Python) |
| \eg<name> call subpattern by name (Oniguruma) |
| \eg'name' call subpattern by name (Oniguruma) |
| \eg<n> call subpattern by absolute number (Oniguruma) |
| \eg'n' call subpattern by absolute number (Oniguruma) |
| \eg<+n> call subpattern by relative number (PCRE extension) |
| \eg'+n' call subpattern by relative number (PCRE extension) |
| \eg<-n> call subpattern by relative number (PCRE extension) |
| \eg'-n' call subpattern by relative number (PCRE extension) |
| . |
| . |
| .SH "CONDITIONAL PATTERNS" |
| .rs |
| .sp |
| (?(condition)yes-pattern) |
| (?(condition)yes-pattern|no-pattern) |
| .sp |
| (?(n)... absolute reference condition |
| (?(+n)... relative reference condition |
| (?(-n)... relative reference condition |
| (?(<name>)... 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 |
| . |
| . |
| .SH "BACKTRACKING CONTROL" |
| .rs |
| .sp |
| The following act immediately they are reached: |
| .sp |
| (*ACCEPT) force successful match |
| (*FAIL) force backtrack; synonym (*F) |
| .sp |
| 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. |
| .sp |
| (*COMMIT) overall failure, no advance of starting point |
| (*PRUNE) advance to next starting character |
| (*SKIP) advance start to current matching position |
| (*THEN) local failure, backtrack to next alternation |
| . |
| . |
| .SH "NEWLINE CONVENTIONS" |
| .rs |
| .sp |
| These are recognized only at the very start of the pattern or after a |
| (*BSR_...) or (*UTF8) or (*UCP) option. |
| .sp |
| (*CR) carriage return only |
| (*LF) linefeed only |
| (*CRLF) carriage return followed by linefeed |
| (*ANYCRLF) all three of the above |
| (*ANY) any Unicode newline sequence |
| . |
| . |
| .SH "WHAT \eR MATCHES" |
| .rs |
| .sp |
| These are recognized only at the very start of the pattern or after a |
| (*...) option that sets the newline convention or UTF-8 or UCP mode. |
| .sp |
| (*BSR_ANYCRLF) CR, LF, or CRLF |
| (*BSR_UNICODE) any Unicode newline sequence |
| . |
| . |
| .SH "CALLOUTS" |
| .rs |
| .sp |
| (?C) callout |
| (?Cn) callout with data n |
| . |
| . |
| .SH "SEE ALSO" |
| .rs |
| .sp |
| \fBpcrepattern\fP(3), \fBpcreapi\fP(3), \fBpcrecallout\fP(3), |
| \fBpcrematching\fP(3), \fBpcre\fP(3). |
| . |
| . |
| .SH AUTHOR |
| .rs |
| .sp |
| .nf |
| Philip Hazel |
| University Computing Service |
| Cambridge CB2 3QH, England. |
| .fi |
| . |
| . |
| .SH REVISION |
| .rs |
| .sp |
| .nf |
| Last updated: 21 November 2010 |
| Copyright (c) 1997-2010 University of Cambridge. |
| .fi |