Regular Expressions 101

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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 = /ssl_subject\="(CN=(?<CN>[^=]*))?(C=(?<C>[^=]*))?(S=(?<S>[^=]*))?(O=(?<O>[^=]*))?(OU=(?<OU>[^=]*))?" ssl_start_time/g; // Alternative syntax using RegExp constructor // const regex = new RegExp('ssl_subject\\="(CN=(?<CN>[^=]*))?(C=(?<C>[^=]*))?(S=(?<S>[^=]*))?(O=(?<O>[^=]*))?(OU=(?<OU>[^=]*))?" ssl_start_time', 'g') const str = `ssl_issuer="CN=DigiCert SHA2 High Assurance Server CA C=US O=DigiCert Inc OU=www.digicert.com" ssl_hash="f41565b049f039e765a0f8be8271a4b4817b7378" ssl_subject="CN=syndication.twitter.com C=US S=California O=Twitter, Inc. OU=Twitter Security" ssl_start_time="Wed Jun 29 00:00:00 2016 UTC" ssl_end_time="Mon Sep 16 12:00:00 2019 UTC" ssl_type="X.509 Certificate" ssl_extended_key_usage="Server Authentication, Client Authentication" ssl_key_length="2048 bits" ssl_key_usage="Digital Signature, Key Encipherment" ssl_subject="CN=*.eu-west-1.webrootcloudav.com" ssl_start_time="Tue Aug 22 00:00:00 2017 UTC" ssl_end_time="Sat Sep 22 12:00:00 2018 UTC" ssl_type="X.509 Certificate" ssl_extended_key_usage="" ssl_key_length="2048 bits" ssl_key_usage="Digital Signature, Non-Repudiation, Key Encipherment" ssl_subject="CN=*.us.static.hrsmart.com C=US S=Virginia O=Deltek, Inc. OU=Security Services" ssl_start_time="Thu Jan 11 00:00:00 2018 UTC" ssl_end_time="Sun Mar 31 12:00:00 2019 UTC" ssl_type="X.509 Certificate" ssl_extended_key_usage="Server Authentication, Client Authentication" ssl_key_length="2048 bits" ssl_key_usage="Digital Signature, Key Encipherment" ssl_subject="CN=*.googleapis.com C=US S=California O=Google Inc" ssl_start_time="Tue Mar 13 18:57:10 2018 UTC" ssl_end_time="Tue Jun 5 18:17:00 2018 UTC" ssl_type="X.509 Certificate" ssl_extended_key_usage="Server Authentication, Client Authentication" ssl_key_length="0 bits" ssl_key_usage="Digital Signature, Certificate Signing, CRL Signing" ssl_subject="CN=subscription.rhsm.redhat.com C=US S=North Carolina O=Red Hat, Inc. OU=Red Hat Network" ssl_start_time="Thu May 18 16:30:24 2017 UTC" ssl_end_time="Sat May 18 16:30:24 2019 UTC" ssl_type="X.509 Certificate" ssl_extended_key_usage="Server Authentication" ssl_key_length="4096 bits" ssl_key_usage=""`; // 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