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Regular Expression Reference: Basic Features

FeatureSyntaxDescriptionExample JGsoft .NET Java Perl PCRE PCRE2 PHP Delphi R JavaScript VBScript XRegExp Python Ruby std::regex Boost Tcl ARE POSIX BRE POSIX ERE GNU BRE GNU ERE Oracle XML XPath
Dot . (dot) Matches any single character except line break characters. Most regex flavors have an option to make the dot match line break characters too. . matches x or (almost) any other character YESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYES
Not a line break \N Matches any single character except line break characters, like the dot, but is not affected by any options that make the dot match all characters including line breaks. \N matches x or any other character that is not a line break V2nono5.128.10YES5.3.4XE7YESnonononononononononononononono
Alternation | (pipe) Causes the regex engine to match either the part on the left side, or the part on the right side. Can be strung together into a series of alternatives. abc|def|xyz matches abc, def or xyz YESYESYESYESYESYESYESYESYESYESYESYESYESYESECMA
extended
egrep
awk
ECMA
extended
egrep
awk
YESnoYESnoYESYESYESYES
Alternation \| (backslash pipe) Causes the regex engine to match either the part on the left side, or the part on the right side. Can be strung together into a series of alternatives. abc\|def\|xyz matches abc, def or xyz nononononononononononononononononononoYESnononono
Alternation Literal line feed not inside a group or character class Causes the regex engine to match either the part on the left side, or the part on the right side. Can be strung together into a series of alternatives. abc
def
xyz
matches abc, def or xyz
nonononononononononononononogrep
egrep
grep
egrep
nononononononono
Alternation Literal line feed inside a group but not inside a character class Causes the group to match either the part on the left side, or the part on the right side. Can be strung together into a series of alternatives. a(bc
de
fg)h
matches abch, adeh or afgh
nononononononononononononononogrep
egrep
nononononononono
Alternation is eager | or \| Alternation returns the first alternative that matches. a|ab matches a in ab YESYESYESYESYESYESYESYESYESYESYESYESYESYESECMAECMAnon/anononoYESYESYES
Alternation is greedy | or \| Alternation returns the longest alternative that matches. a|ab matches ab in ab nonononononononononononononoextended
grep
egrep
awk
extended
grep
egrep
awk
YESn/aYESYESYESnonono
FeatureSyntaxDescriptionExample JGsoft .NET Java Perl PCRE PCRE2 PHP Delphi R JavaScript VBScript XRegExp Python Ruby std::regex Boost Tcl ARE POSIX BRE POSIX ERE GNU BRE GNU ERE Oracle XML XPath

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Regex Reference
Introduction
Table of Contents
Quick Reference
Characters
Basic Features
Character Classes
Shorthands
Anchors
Word Boundaries
Quantifiers
Unicode
Capturing Groups & Backreferences
Named Groups & Backreferences
Special Groups
Mode Modifiers
Recursion & Balancing Groups
Replacement Reference
Characters
Matched Text & Backreferences
Context & Case Conversion
Conditionals
More on This Site
Introduction
Regular Expressions Quick Start
Regular Expressions Tutorial
Replacement Strings Tutorial
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