| Syntax | Feature |
|---|
Any character except [\^$.|?*+() | Literal character |
\ followed by any of [\^$.|?*+(){} | Backslash escapes a metacharacter |
. | Any character |
| | Alternation |
\| | Alternation |
? | Greedy quantifier |
\? | Greedy quantifier |
?? | Lazy quantifier |
?+ | Possessive quantifier |
* | Greedy quantifier |
*? | Lazy quantifier |
*+ | Possessive quantifier |
+ | Greedy quantifier |
\+ | Greedy quantifier |
+? | Lazy quantifier |
++ | Possessive quantifier |
{ and } | Literal curly braces |
{n} where n is an integer >= 1 | Fixed quantifier |
{n,m} where n >= 0 and m >= n | Greedy quantifier |
{n,} where n >= 0 | Greedy quantifier |
{,m} where m >= 1 | Greedy quantifier |
\{n\} where n is an integer >= 1 | Fixed quantifier |
\{n,m\} where n >= 0 and m >= n | Greedy quantifier |
\{n,\} where n >= 0 | Greedy quantifier |
\{,m\} where m >= 1 | Greedy quantifier |
{n,m}? where n >= 0 and m >= n | Lazy quantifier |
{n,}? where n >= 0 | Lazy quantifier |
{,m}? where m >= 1 | Lazy quantifier |
{n,m}+ where n >= 0 and m >= n | Possessive quantifier |
{n,}+ where n >= 0 | Possessive quantifier |
^ | String anchor |
^ | Line anchor |
$ | String anchor |
$ | Line anchor |
\a | Character escape |
\A | String anchor |
\A | Attempt anchor |
\b | Word boundary |
\b | Backspace character |
\B | Word non-boundary |
\B | Backslash character |
\c | XML shorthand |
\ca through \cz | Control character escape |
\cA through \cZ | Control character escape |
\C | XML shorthand |
\d | Digits shorthand |
\D | Non-digits shorthand |
\e | Escape character |
\f | Form feed character |
\g{name} | Named backreference |
\g-1, \g-2, etc. | Relative Backreference |
\g{-1}, \g{-2}, etc. | Relative Backreference |
\g1 through \g99 | Backreference |
\g{1} through \g{99} | Backreference |
\g<name> where “name” is the name of a capturing group | Named subroutine call |
\g<name> where “name” is the name of a capturing group | Named backreference |
\g'name' where “name” is the name of a capturing group | Named subroutine call |
\g'name' where “name” is the name of a capturing group | Named backreference |
\g<0> | Recursion |
\g'0' | Recursion |
\g<1> where 1 is the number of a capturing group | Subroutine call |
\g<1> where 1 is the number of a capturing group | Backreference |
\g'1' where 1 is the number of a capturing group | Subroutine call |
\g'1' where 1 is the number of a capturing group | Backreference |
\g<-1> where -1 is a negative integer | Relative subroutine call |
\g<-1> where -1 is a negative integer | Relative backreference |
\g'-1' where -1 is a negative integer | Relative subroutine call |
\g'-1' where -1 is a negative integer | Relative backreference |
\g<+1> where +1 is a positive integer | Forward subroutine call |
\g'+1' where +1 is a positive integer | Forward subroutine call |
\G | Attempt anchor |
\G | Match anchor |
\h | Hexadecimal digit shorthand |
\h | Horizontal whitespace shorthand |
\H | Non-hexadecimal digit shorthand |
\H | Non-horizontal whitespace shorthand |
\i | XML shorthand |
\I | XML shorthand |
\k<name> | Named backreference |
\k'name' through \k'99' | Named backreference |
\k{name} | Named backreference |
\k<1> through \k<99> | Backreference |
\k'1' through \k'99' | Backreference |
\k<-1>, \k<-2>, etc. | Relative Backreference |
\k'-1', \k'-2', etc. | Relative Backreference |
\K | Keep text out of the regex match |
\l | Lowercase shorthand |
\L | Non-lowercase shorthand |
\m | Tcl start of word boundary |
\M | Tcl end of word boundary |
\n | Line feed character |
\N | Not a line break |
| Literal CRLF, LF, or CR line break | Line break |
\o{7777} where 7777 is any octal number | Octal escape |
\pL where L is a Unicode category | Unicode category |
\PL where L is a Unicode category | Unicode category |
\p{L} where L is a Unicode category | Unicode category |
\p{IsL} where L is a Unicode category | Unicode category |
\p{Category} | Unicode category |
\p{IsCategory} | Unicode category |
\p{Script} | Unicode script |
\p{IsScript} | Unicode script |
\p{Block} | Unicode block |
\p{InBlock} | Unicode block |
\p{IsBlock} | Unicode block |
\P{Property} | Negated Unicode property |
\p{^Property} | Negated Unicode property |
\P{^Property} | Unicode property |
\Q…\E | Escape sequence |
\r | Carriage return character |
\R | Line break |
\s | Whitespace shorthand |
\S | Non-whitespace shorthand |
\t | Tab character |
\u | Uppercase shorthand |
\uFFFF where FFFF are 4 hexadecimal digits | Unicode code point |
\u{FFFF} where FFFF are 1 to 4 hexadecimal digits | Unicode code point |
\U | Non-uppercase shorthand |
\v | Vertical tab character |
\v | Vertical whitespace shorthand |
\V | Non-vertical whitespace shorthand |
\w | Word character shorthand |
\W | Non-word character shorthand |
\xFF where FF are 2 hexadecimal digits | Hexadecimal escape |
\xFFFF where FFFF are 4 hexadecimal digits | Unicode code point |
\x{FFFF} where FFFF are 1 to 4 hexadecimal digits | Unicode code point |
\X | Unicode grapheme |
\y | Tcl word boundary |
\Y | Tcl word non-boundary |
\Z | String anchor |
\z | String anchor |
\0 | NULL escape |
\1 through \7 | Octal escape |
\1 through \9 | Backreference |
\10 through \77 | Octal escape |
\10 through \99 | Backreference |
\100 through \377 | Octal escape |
\01 through \0377 | Octal escape |
\` | String anchor |
\` | Attempt anchor |
\' | String anchor |
\< | GNU word boundary |
\> | GNU word boundary |
[[:<:]] | POSIX word boundary |
[[:>:]] | POSIX word boundary |
(regex) | Capturing group |
\(regex\) | Capturing group |
(?:regex) | Non-capturing group |
(?<name>regex) | Named capturing group |
(?'name'regex) | Named capturing group |
(?#comment) | Comment |
(?|regex) | Branch reset group |
(?>regex) | Atomic group |
(?=regex) | Positive lookahead |
(?!regex) | Negative lookahead |
(?<=regex) | Positive lookbehind |
(?<!regex) | Negative lookbehind |
(?(?=regex)then|else) where (?=regex) is any valid lookaround and then and else are any valid regexes | Lookaround conditional |
(?(regex)then|else) where regex, then, and else are any valid regexes and regex is not the name of a capturing group | Implicit lookahead conditional |
(?(name)then|else) where name is the name of a capturing group and then and else are any valid regexes | Named conditional |
(?(<name>)then|else) where name is the name of a capturing group and then and else are any valid regexes | Named conditional |
(?('name')then|else) where name is the name of a capturing group and then and else are any valid regexes | Named conditional |
(?(1)then|else) where 1 is the number of a capturing group and then and else are any valid regexes | Conditional |
(?(-1)then|else) where -1 is a negative integer and then and else are any valid regexes | Relative conditional |
(?(+1)then|else) where +1 is a positive integer and then and else are any valid regexes | Forward conditional |
(?(+1)then|else) where 1 is the number of a capturing group and then and else are any valid regexes | Conditional |
(?<capture-subtract>regex) where “capture” and “subtract” are group names and “regex” is any regex | Balancing group |
(?'capture-subtract'regex) where “capture” and “subtract” are group names and “regex” is any regex | Balancing group |
(?&name) where “name” is the name of a capturing group | Named subroutine call |
(?(DEFINE)regex) where “regex” is any regex | Subroutine definitions |
(?P<name>regex) | Named capturing group |
(?P=name) | Named backreference |
(?P=1) through (?P=99) | Backreference |
(?P>name) where “name” is the name of a capturing group | Named subroutine call |
(?R) | Recursion |
(?0) | Recursion |
(?1) where 1 is the number of a capturing group | Subroutine call |
(?-1) where -1 is a negative integer | Relative subroutine call |
(?+1) where +1 is a positive integer | Forward subroutine call |
