RegexBuddy—Better than a regular expression reference!

Regular Expressions Quick Reference

This quick reference is a summary of all the regex syntax that is listed in the full reference tables, without any explanation. You can use this table if you’ve seen some syntax in somebody else’s regex and you have no idea what feature that syntax is for. Follow the link to learn more about the syntax in the tutorial. Since the full reference tables cover a variety of regex flavors, this quick reference may have multiple entries for the same syntax with links to different sections in the tutorial if different regex flavors use the same syntax for different features.

If you already know the feature you want but forgot which syntax to use, look up the feature in the regex reference table of contents instead.

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

Character Class Syntax	Feature
Any character except `^-]\`	Literal character
`\` (backslash) followed by any of `^-]\`	Backslash escapes a metacharacter
`\`	Literal backslash
`-` between two tokens that each specify a single character	Range
`^` immediately after the opening `[`	Negated character class
`[`	Literal opening bracket
`[`	Nested character class
`[base-[subtract]]`	Character class subtraction
`[base&&[intersect]]`	Character class intersection
`[base&&intersect]`	Character class intersection
`[:alpha:]`	POSIX class
`[:^alpha:]`	Negated POSIX class
`\p{Alpha}`	POSIX class
`\p{IsAlpha}`	POSIX class
`[.span-ll.]`	POSIX collation sequence
`[=x=]`	POSIX character equivalence