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

/
/

Test String

Code Generator

Language

Generated Code

const regex = /(^type=AVC msg=audit\((?<time>\w+).*: apparmor=\"(?<resolution>\w+)\" operation=\"(?<operation>\w+)\"( profile=\"(?<profile>[^ ]+)\"){0,1}( name=\"(?<name>[^ ]+)\"){0,1} pid=(?<pid>\d+) comm=\"{0,1}(?<comm>[^ ]+)\"{0,1}( requested_mask=\"(?<requested_mask>\w+)\" denied_mask=\"(?<denied_mask>\w+)\" fsuid=(?<fsuid>\d+))?|^type=(?<type>\w+) msg=audit\((?<time1>\w+).*: pid=(?<pid1>\d+) uid=(?<uid>\d+) .* msg='(?<message>.*)'|type=NETFILTER_CFG msg=audit\((?<time2>\w+).*: table=(?<table>[^ ]+) family=(?<family>\d+) entries=(?<entries>\d+)|type=ANOM_PROMISCUOUS msg=audit\((?<time3>\w+).*: dev=(?<device>[^ ]+) prom=(?<prom>\d+) old_prom=(?<old_prom>\d+).*)|type=DAEMON\w+ msg=audit\((?<time4>\w+).*: (?<message1>.*)|type=CONFIG_CHANGE msg=audit\((?<time5>\w+).*: (?<message2>.*)/; // Alternative syntax using RegExp constructor // const regex = new RegExp('(^type=AVC msg=audit\\((?<time>\\w+).*: apparmor=\\"(?<resolution>\\w+)\\" operation=\\"(?<operation>\\w+)\\"( profile=\\"(?<profile>[^ ]+)\\"){0,1}( name=\\"(?<name>[^ ]+)\\"){0,1} pid=(?<pid>\\d+) comm=\\"{0,1}(?<comm>[^ ]+)\\"{0,1}( requested_mask=\\"(?<requested_mask>\\w+)\\" denied_mask=\\"(?<denied_mask>\\w+)\\" fsuid=(?<fsuid>\\d+))?|^type=(?<type>\\w+) msg=audit\\((?<time1>\\w+).*: pid=(?<pid1>\\d+) uid=(?<uid>\\d+) .* msg=\'(?<message>.*)\'|type=NETFILTER_CFG msg=audit\\((?<time2>\\w+).*: table=(?<table>[^ ]+) family=(?<family>\\d+) entries=(?<entries>\\d+)|type=ANOM_PROMISCUOUS msg=audit\\((?<time3>\\w+).*: dev=(?<device>[^ ]+) prom=(?<prom>\\d+) old_prom=(?<old_prom>\\d+).*)|type=DAEMON\\w+ msg=audit\\((?<time4>\\w+).*: (?<message1>.*)|type=CONFIG_CHANGE msg=audit\\((?<time5>\\w+).*: (?<message2>.*)', '') const str = `type=DAEMON_START msg=audit(1450609493.002:6827): auditd start, ver=2.4 format=raw kernel=4.3.0 auid=4294967295 pid=2491 subj=unconfined res=success`; // Reset `lastIndex` if this regex is defined globally // regex.lastIndex = 0; let m; if ((m = regex.exec(str)) !== null) { // The result can be accessed through the `m`-variable. m.forEach((match, groupIndex) => { console.log(`Found match, group ${groupIndex}: ${match}`); }); }

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 JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions