Single characters:

RE Meaning
. any character, possibly including newline (s=true)
[xyz] character class
[^xyz] negated character class
\d Perl character class
\D negated Perl character class
[[:alpha:]] ASCII character class
[[:^alpha:]] negated ASCII character class
\pN Unicode character class (one-letter name)
\p{Greek} Unicode character class
\PN negated Unicode character class (one-letter name)
\P{Greek} negated Unicode character class

Composites:

RE Meaning
xy «x» followed by «y»
x|y «x» or «y» (prefer «x»)

Repetitions:

RE Meaning
x* zero or more «x», prefer more
x+ one or more «x», prefer more
x? zero or one «x», prefer one
x{n,m} «n» or «n»+1 or ... or «m» «x», prefer more
x{n,} «n» or more «x», prefer more
x{n} exactly «n» of «x»
x*? zero or more «x», prefer fewer
x+? one or more «x», prefer fewer
x?? zero or one «x», prefer zero
x{n,m}? «n» or «n»+1 or ... or «m» «x», prefer fewer
x{n,}? «n» or more «x», prefer fewer
x{n}? exactly «n» of «x»
x{} (== x*) NOT SUPPORTED vim
x{-} (== x*?) NOT SUPPORTED vim
x{-n} (== x{n}?) NOT SUPPORTED vim
x= (== x?) NOT SUPPORTED vim

Implementation restriction: The counting forms «x{n,m}», «x{n,}», and «x{n}» reject forms that create a minimum or maximum repetition count above 1000. Unlimited repetitions are not subject to this restriction.

Possessive repetitions:

RE Meaning
x*+ zero or more «x», possessive NOT SUPPORTED
x++ one or more «x», possessive NOT SUPPORTED
x?+ zero or one «x», possessive NOT SUPPORTED
x{n,m}+ «n» or ... or «m» «x», possessive NOT SUPPORTED
x{n,}+ «n» or more «x», possessive NOT SUPPORTED
x{n}+ exactly «n» of «x», possessive NOT SUPPORTED

Grouping:

RE Meaning
(re) numbered capturing group (submatch)
(?P<name>re) named & numbered capturing group (submatch)
(?<name>re) named & numbered capturing group (submatch) NOT SUPPORTED
(?'name're) named & numbered capturing group (submatch) NOT SUPPORTED
(?:re) non-capturing group
(?flags) set flags within current group; non-capturing
(?flags:re) set flags during re; non-capturing
(?#text) comment NOT SUPPORTED
(?|x|y|z) branch numbering reset NOT SUPPORTED
(?>re) possessive match of «re» NOT SUPPORTED
re@> possessive match of «re» NOT SUPPORTED vim
%(re) non-capturing group NOT SUPPORTED vim

Flags:

RE Meaning
i case-insensitive (default false)
m multi-line mode: «^» and «$» match begin/end line in addition to begin/end text (default false)
s let «.» match «\n» (default false)
U ungreedy: swap meaning of «x*» and «x*?», «x+» and «x+?», etc (default false)

Flag syntax is «xyz» (set) or «-xyz» (clear) or «xy-z» (set «xy», clear «z»).

Empty strings:

RE Meaning
^ at beginning of text or line («m»=true)
$ at end of text (like «\z» not «\Z») or line («m»=true)
\A at beginning of text
\b at ASCII word boundary («\w» on one side and «\W», «\A», or «\z» on the other)
\B not at ASCII word boundary
\G at beginning of subtext being searched NOT SUPPORTED pcre
\G at end of last match NOT SUPPORTED perl
\Z at end of text, or before newline at end of text NOT SUPPORTED
\z at end of text
(?=re) before text matching «re» NOT SUPPORTED
(?!re) before text not matching «re» NOT SUPPORTED
(?<=re) after text matching «re» NOT SUPPORTED
(?<!re) after text not matching «re» NOT SUPPORTED
re& before text matching «re» NOT SUPPORTED vim
re@= before text matching «re» NOT SUPPORTED vim
re@! before text not matching «re» NOT SUPPORTED vim
re@<= after text matching «re» NOT SUPPORTED vim
re@<! after text not matching «re» NOT SUPPORTED vim
\zs sets start of match (= \K) NOT SUPPORTED vim
\ze sets end of match NOT SUPPORTED vim
\%^ beginning of file NOT SUPPORTED vim
\%$ end of file NOT SUPPORTED vim
\%V on screen NOT SUPPORTED vim
\%# cursor position NOT SUPPORTED vim
\%'m mark «m» position NOT SUPPORTED vim
\%23l in line 23 NOT SUPPORTED vim
\%23c in column 23 NOT SUPPORTED vim
\%23v in virtual column 23 NOT SUPPORTED vim

Escape sequences:

RE Meaning
\a bell (== \007)
\f form feed (== \014)
\t horizontal tab (== \011)
\n newline (== \012)
\r carriage return (== \015)
\v vertical tab character (== \013)
\* literal «*», for any punctuation character «*»
\123 octal character code (up to three digits)
\x7F hex character code (exactly two digits)
\x{10FFFF} hex character code
\C match a single byte even in UTF-8 mode
\Q...\E literal text «...» even if «...» has punctuation
\1 backreference NOT SUPPORTED
\b backspace NOT SUPPORTED (use «\010»)
\cK control char ^K NOT SUPPORTED (use «\001» etc)
\e escape NOT SUPPORTED (use «\033»)
\g1 backreference NOT SUPPORTED
\g{1} backreference NOT SUPPORTED
\g{+1} backreference NOT SUPPORTED
\g{-1} backreference NOT SUPPORTED
\g{name} named backreference NOT SUPPORTED
\g<name> subroutine call NOT SUPPORTED
\g'name' subroutine call NOT SUPPORTED
\k<name> named backreference NOT SUPPORTED
\k'name' named backreference NOT SUPPORTED
\lX lowercase «X» NOT SUPPORTED
\ux uppercase «x» NOT SUPPORTED
\L...\E lowercase text «...» NOT SUPPORTED
\K reset beginning of «$0» NOT SUPPORTED
\N{name} named Unicode character NOT SUPPORTED
\R line break NOT SUPPORTED
\U...\E upper case text «...» NOT SUPPORTED
\X extended Unicode sequence NOT SUPPORTED
\%d123 decimal character 123 NOT SUPPORTED vim
\%xFF hex character FF NOT SUPPORTED vim
\%o123 octal character 123 NOT SUPPORTED vim
\%u1234 Unicode character 0x1234 NOT SUPPORTED vim
\%U12345678 Unicode character 0x12345678 NOT SUPPORTED vim

Character class elements:

RE Meaning
x single character
A-Z character range (inclusive)
\d Perl character class
[:foo:] ASCII character class «foo»
\p{Foo} Unicode character class «Foo»
\pF Unicode character class «F» (one-letter name)

Named character classes as character class elements:

RE Meaning
[\d] digits (== \d)
[^\d] not digits (== \D)
[\D] not digits (== \D)
[^\D] not not digits (== \d)
[[:name:]] named ASCII class inside character class (== [:name:])
[^[:name:]] named ASCII class inside negated character class (== [:^name:])
[\p{Name}] named Unicode property inside character class (== \p{Name})
[^\p{Name}] named Unicode property inside negated character class (== \P{Name})

Perl character classes (all ASCII-only):

RE Meaning
\d digits (== [0-9])
\D not digits (== [^0-9])
\s whitespace (== [\t\n\f\r ])
\S not whitespace (== [^\t\n\f\r ])
\w word characters (== [0-9A-Za-z_])
\W not word characters (== [^0-9A-Za-z_])
\h horizontal space NOT SUPPORTED
\H not horizontal space NOT SUPPORTED
\v vertical space NOT SUPPORTED
\V not vertical space NOT SUPPORTED

ASCII character classes:

| RE | Meaning | |:—:|:—:| | [[:alnum:]] | alphanumeric (== [0-9A-Za-z]) | | [[:alpha:]] | alphabetic (== [A-Za-z]) | | [[:ascii:]] | ASCII (== [\x00-\x7F]) | | [[:blank:]] | blank (== [\t ]) | | [[:cntrl:]] | control (== [\x00-\x1F\x7F]) | | [[:digit:]] | digits (== [0-9]) | | [[:graph:]] | graphical (== [!-~] == [A-Za-z0-9!"#$%&'()*+,\-./:;<=>?@[\\\]^_{|}~]) | | [[:lower:]] | lower case (== [a-z]) | | [[:print:]] | printable (== [ -~] == [ [:graph:]]) | | [[:punct:]] | punctuation (== [!-/:-@[-{-~]) | | [[:space:]] | whitespace (== [\t\n\v\f\r ]) | | [[:upper:]] | upper case (== [A-Z]) | | [[:word:]] | word characters (== [0-9A-Za-z_]) | | [[:xdigit:]] | hex digit (== [0-9A-Fa-f]) |

Unicode character class names - general category:

RE Meaning
C other
Cc control
Cf format
Cn unassigned code points NOT SUPPORTED
Co private use
Cs surrogate
L letter
LC cased letter NOT SUPPORTED
L& cased letter NOT SUPPORTED
Ll lowercase letter
Lm modifier letter
Lo other letter
Lt titlecase letter
Lu uppercase letter
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 math symbol
So other symbol
Z separator
Zl line separator
Zp paragraph separator
Zs space separator

Unicode character class names - scripts:

  • Ahom
  • Anatolian_Hieroglyphs
  • Arabic
  • Armenian
  • Avestan
  • Balinese
  • Bamum
  • Bassa_Vah
  • Batak
  • Bengali
  • Bopomofo
  • Brahmi
  • Braille
  • Buginese
  • Buhid
  • Canadian_Aboriginal
  • Carian
  • Caucasian_Albanian
  • Chakma
  • Cham
  • Cherokee
  • Common
  • Coptic
  • Cuneiform
  • Cypriot
  • Cyrillic
  • Deseret
  • Devanagari
  • Duployan
  • Egyptian_Hieroglyphs
  • Elbasan
  • Ethiopic
  • Georgian
  • Glagolitic
  • Gothic
  • Grantha
  • Greek
  • Gujarati
  • Gurmukhi
  • Han
  • Hangul
  • Hanunoo
  • Hatran
  • Hebrew
  • Hiragana
  • Imperial_Aramaic
  • Inherited
  • Inscriptional_Pahlavi
  • Inscriptional_Parthian
  • Javanese
  • Kaithi
  • Kannada
  • Katakana
  • Kayah_Li
  • Kharoshthi
  • Khmer
  • Khojki
  • Khudawadi
  • Lao
  • Latin
  • Lepcha
  • Limbu
  • Linear_A
  • Linear_B
  • Lisu
  • Lycian
  • Lydian
  • Mahajani
  • Malayalam
  • Mandaic
  • Manichaean
  • Meetei_Mayek
  • Mende_Kikakui
  • Meroitic_Cursive
  • Meroitic_Hieroglyphs
  • Miao
  • Modi
  • Mongolian
  • Mro
  • Multani
  • Myanmar
  • Nabataean
  • New_Tai_Lue
  • Nko
  • Ogham
  • Ol_Chiki
  • Old_Hungarian
  • Old_Italic
  • Old_North_Arabian
  • Old_Permic
  • Old_Persian
  • Old_South_Arabian
  • Old_Turkic
  • Oriya
  • Osmanya
  • Pahawh_Hmong
  • Palmyrene
  • Pau_Cin_Hau
  • Phags_Pa
  • Phoenician
  • Psalter_Pahlavi
  • Rejang
  • Runic
  • Samaritan
  • Saurashtra
  • Sharada
  • Shavian
  • Siddham
  • SignWriting
  • Sinhala
  • Sora_Sompeng
  • Sundanese
  • Syloti_Nagri
  • Syriac
  • Tagalog
  • Tagbanwa
  • Tai_Le
  • Tai_Tham
  • Tai_Viet
  • Takri
  • Tamil
  • Telugu
  • Thaana
  • Thai
  • Tibetan
  • Tifinagh
  • Tirhuta
  • Ugaritic
  • Vai
  • Warang_Citi
  • Yi

Vim character classes:

RE Meaning
\i identifier character NOT SUPPORTED vim
\I «\i» except digits NOT SUPPORTED vim
\k keyword character NOT SUPPORTED vim
\K «\k» except digits NOT SUPPORTED vim
\f file name character NOT SUPPORTED vim
\F «\f» except digits NOT SUPPORTED vim
\p printable character NOT SUPPORTED vim
\P «\p» except digits NOT SUPPORTED vim
\s whitespace character (== [ \t]) NOT SUPPORTED vim
\S non-white space character (== [^ \t]) NOT SUPPORTED vim
\d digits (== [0-9]) vim
\D not «\d» vim
\x hex digits (== [0-9A-Fa-f]) NOT SUPPORTED vim
\X not «\x» NOT SUPPORTED vim
\o octal digits (== [0-7]) NOT SUPPORTED vim
\O not «\o» NOT SUPPORTED vim
\w word character vim
\W not «\w» vim
\h head of word character NOT SUPPORTED vim
\H not «\h» NOT SUPPORTED vim
\a alphabetic NOT SUPPORTED vim
\A not «\a» NOT SUPPORTED vim
\l lowercase NOT SUPPORTED vim
\L not lowercase NOT SUPPORTED vim
\u uppercase NOT SUPPORTED vim
\U not uppercase NOT SUPPORTED vim
\_x «\x» plus newline, for any «x» NOT SUPPORTED vim

Vim flags:

RE Meaning
\c ignore case NOT SUPPORTED vim
\C match case NOT SUPPORTED vim
\m magic NOT SUPPORTED vim
\M nomagic NOT SUPPORTED vim
\v verymagic NOT SUPPORTED vim
\V verynomagic NOT SUPPORTED vim
\Z ignore differences in Unicode combining characters NOT SUPPORTED vim

Magic:

RE Meaning
(?{code}) arbitrary Perl code NOT SUPPORTED perl
(??{code}) postponed arbitrary Perl code NOT SUPPORTED perl
(?n) recursive call to regexp capturing group «n» NOT SUPPORTED
(?+n) recursive call to relative group «+n» NOT SUPPORTED
(?-n) recursive call to relative group «-n» NOT SUPPORTED
(?C) PCRE callout NOT SUPPORTED pcre
(?R) recursive call to entire regexp (== (?0)) NOT SUPPORTED
(?&name) recursive call to named group NOT SUPPORTED
(?P=name) named backreference NOT SUPPORTED
(?P>name) recursive call to named group NOT SUPPORTED
(?(cond)true|false) conditional branch NOT SUPPORTED
(?(cond)true) conditional branch NOT SUPPORTED
(*ACCEPT) make regexps more like Prolog NOT SUPPORTED
(*COMMIT) NOT SUPPORTED
(*F) NOT SUPPORTED
(*FAIL) NOT SUPPORTED
(*MARK) NOT SUPPORTED
(*PRUNE) NOT SUPPORTED
(*SKIP) NOT SUPPORTED
(*THEN) NOT SUPPORTED
(*ANY) set newline convention NOT SUPPORTED
(*ANYCRLF) NOT SUPPORTED
(*CR) NOT SUPPORTED
(*CRLF) NOT SUPPORTED
(*LF) NOT SUPPORTED
(*BSR_ANYCRLF) set \R convention NOT SUPPORTED pcre
(*BSR_UNICODE) NOT SUPPORTED pcre