Regular Expressions - Experts Page

C               Other
Cc              Control                - The ASCII and Latin-1 control characters HT, LF, CR, NULL, Escape, NEL, ...)
Cf              Format                 - Non-visible characters for basic formatting (zero width joiner,
                                         activate arabic form shaping, ...)
Cn              Unassigned             - Codepoints that have no characters assigned
Co              Private use            - Company logos, ...
Cs              Surrogate              - No characters, reserved for use in UTF-16 for specifying characters outside basic
                                         multilingual plane

L               Letter
L&              Case letters           - A composite matching all Ll, Lu and Lt characters
Ll              Lower case letter
Lm              Modifier letter        - A small set of letter-like special-use characters
Lo              Other letter           - Letters that have no case and aren't modifiers (hebrew, arabic, bengali, tibetan,
                                         japanese, ...)
Lt              Title case letter      - Letters that appear at the start of a word (e.g. the character Dž is the title case of
                                         the lowercase dž and of the uppercase DŽ)
Lu              Upper case letter

M               Mark
Mc              Spacing mark          - Modification characters that take up space (mostly "vowel signs" in bengali, gujarati,
                                        tamil, telugu, kannada, sinhala, ...)
Me              Enclosing mark        - A small set of marks that can enclose other characters (circles, squares, diamonds,
                                        keycaps, ...)
Mn              Non-spacing mark      - Characters that modify other characters, such as accents, umlauts, "vowel signs",
                                        tone marks, ...

N               Number
Nd              Decimal number        - Zero to nine, in various scripts (not including chinese, japanese and korean):
                                        8, ٣, ໖ or ꘧
Nl              Letter number         - Mostly roman numerals (such as ⅶ, ↉, 〨, 〇, ᛯ or ᛰ)
No              Other number          - Other numbers as ⑲, ፷, ₅, ⅞ or ៵

P               Punctuation
Pc              Connector punctuation - A few punctuation characters with special linguistic meaning such as underscore
Pd              Dash punctuation      - Hyphens and dashes of all sorts
Pe              Close punctuation     - Characters like ), ], }, ⟫ 】, ︾, ...
Pf              Final punctuation     - Characters like », ›, ”, ’, ...
Pi              Initial punctuation   - Characters like «, ‘, ‛, ‹, ...
Po              Other punctuation     - Characters like !, ", *, :, @, ߷, ‱, ⁜, ፣ or ¶
Ps              Open punctuation      - Characters like (, [, {, ༼, ❰, ﹃, ...

S               Symbol
Sc              Currency symbol       - Characters like $, £, ¤, ¥, ₠, ௹, €, ₧, ₪d or ﷼
Sk              Modifier symbol       - Mostly versions of the combining characters, but as full-fledged characters in their own
                                        right such as ^, `, ¸, ˚ or ˨
Sm              Mathematical symbol   - Characters like +, >, =, ±, ÷, ⅀, ∀, ∜, ∰, ≹
                                        or ﬩ (not including '-' which is in Pd)
So              Other symbol          - Various Dingbats, box-drawing symbols, Braille patterns, ...
                                        (¦, ©, מ, ࿏, ℡, ⌫, ▧, ,  or ☣) 

Z               Separator
Zl              Line separator        - Just the LINE SEPARATOR characters (U+2028)
Zp              Paragraph separator   - Just the PARAGRAPH SEPARATOR character (U+2029)
Zs              Space separator       - Various spacing characters such as normal space, non-breaking space, em-space,
                                        thin space, ...

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.

[[:alnum:]]     An alphanumeric character: [[:alpha:][:digit:]]
[[:alpha:]]     An ascii character: [[:lower:][:upper:]]
[[:ascii:]]     Codepoints U+0000 .. U+007F
[[:blank:]]     A space or a tab: [ \t]
[[:cntrl:]]     An ascii control character: U+0000 to U+001f
[[:digit:]]     A decimal digit: [0123456789]
[[:graph:]]     A visible ascii character: [[:alnum:][:punct:]]
[[:lower:]]     A lower-case ascii character
[[:print:]]     A printable character: [ [:graph:]] (including space U+0020)
[[:punct:]]     Punctuation: One of !"#$%&`()*+,-./:;<=>?@[\]^_`{|}~
[[:space:]]     A whitespace character: [ \t\n\x{0b}\f\r]
[[:upper:]]     An upper-case ASCII character
[[:word:]]      Same as \w
[[:xdigit:]]    A hexadecimal digit: [[:digit:]abcdefABCDEF]

[[:^xxxx:]]     negative POSIX named set

^               The beginning of the string
                  (plus after newlines in multiline mode)
$               The end of the string
                  (plus before newline at end of string)
                  (plus before internal newline in multiline mode)
\b              Word boundary
                  the position is between a word character (\w) and a non-word character (\W)
                  beware: only ASCII characters are regarded as word characters
\B              Not a word boundary
[[:<:]]         start of a word
[[:>:]]         end of a word
\A              start of the string
\Z              end of the string
                  (plus before newline at end of string)
\z              end of the string
\G              first matching position in string

X?              X, one single occurrence or none at all, equivalent to X{0,1}, greedy
X?+             X, one single occurrence or none at all, possessive
X??             X, one single occurrence or none at all, lazy
X*              X, zero or more times, equivalent to X{0,}, greedy
X*+             X, zero or more times, possessive
X*?             X, zero or more times, lazy
X+              X, one or more times, equivalent to X{1,}, greedy
X++             X, one or more times, possessive
X+?             X, one or more times, lazy
X{n}            X, exactly n times
X{min,}         X, at least min times, greedy
X{min,}+        X, at least min times, possessive
X{min,}?        X, at least min times, lazy
X{min,max}      X, at least min but not more than max times, greedy
X{min,max}+     X, at least min but not more than max times, possessive
X{min,max}?     X, at least min but not more than max times, lazy