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

/
/
g

Test String

Code Generator

Language

Generated Code

const regex = /.*\d\s(\d+-\d+-\d+T\d+:\d+:\d+)(\+\d+:\d+)\s.*?\s(\d+,\d+\/\d+\/\d+) .*? .*? .*? (\d+:\d+:\d+),\d+,THREAT,(url),(\d+,\d+\/\d+\/\d+ \d+:\d+:\d+),(\d+\.\d+\.\d+\.\d+),.*/g; // Alternative syntax using RegExp constructor // const regex = new RegExp('.*\\d\\s(\\d+-\\d+-\\d+T\\d+:\\d+:\\d+)(\\+\\d+:\\d+)\\s.*?\\s(\\d+,\\d+\\\/\\d+\\\/\\d+) .*? .*? .*? (\\d+:\\d+:\\d+),\\d+,THREAT,(url),(\\d+,\\d+\\\/\\d+\\\/\\d+ \\d+:\\d+:\\d+),(\\d+\\.\\d+\\.\\d+\\.\\d+),.*', 'g') const str = `<14>1 2017-07-17T12:06:14+00:00 PA-VM 1,2017/07/17 - - - 05:11:16,007055000020053,THREAT,url,1,2017/07/17 05:11:16,10.10.201.182,13.107.4.50,10.10.6.64,13.107.4.50,Segmented_to_PVT,,,ms-update,vsys1,User Zone,PUB Zone,ethernet1/1,ethernet1/3,Log_Forwarding_Profile,2017/07/17 05:11:16,41324,1,56881,80,3969,80,0x40b000,tcp,alert,"au.download.windowsupdate.com/c/msdownload/update/software/secu/2017/07/windows10.0-kb4025339-x64_5_630b3945c0f68f2e3de0d8779d1e1e6c036e19ca.psf",(9999),computer-and-internet-info,informational,client-to-server,437956,0x0,10.0.0.0-10.255.255.255,United States,0,,0,,,3,,,AppThreat-0-0,0x0,,,,,,0,0,0,0,0,,PA-VM,,,,get,0,,0,,N`; // Reset `lastIndex` if this regex is defined globally // regex.lastIndex = 0; let m; while ((m = regex.exec(str)) !== null) { // This is necessary to avoid infinite loops with zero-width matches if (m.index === regex.lastIndex) { regex.lastIndex++; } // 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