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 = /(-----BEGIN CERTIFICATE-----(?:[\s\S]*?)-----END CERTIFICATE-----)/g; // Alternative syntax using RegExp constructor // const regex = new RegExp('(-----BEGIN CERTIFICATE-----(?:[\\s\\S]*?)-----END CERTIFICATE-----)', 'g') const str = `-----BEGIN CERTIFICATE----- MIID+jCCAuKgAwIBAgIDAjbSMA0GCSqGSIb3DQEBBQUAMEIxCzAJBgNVBAYTAlVT MRYwFAYDVQQKEw1HZW9UcnVzdCBJbmMuMRswGQYDVQQDExJHZW9UcnVzdCBHbG9i YWwgQ0EwHhcNMTAwMjI2MjEzMjMxWhcNMjAwMjI1MjEzMjMxWjBhMQswCQYDVQQG EwJVUzEWMBQGA1UEChMNR2VvVHJ1c3QgSW5jLjEdMBsGA1UECxMURG9tYWluIFZh bGlkYXRlZCBTU0wxGzAZBgNVBAMTEkdlb1RydXN0IERWIFNTTCBDQTCCASIwDQYJ KoZIhvcNAQEBBQADggEPADCCAQoCggEBAKa7jnrNpJxiV9RRMEJ7ixqy0ogGrTs8 KRMMMbxp+Z9alNoGuqwkBJ7O1KrESGAA+DSuoZOv3gR+zfhcIlINVlPrqZTP+3RE 60OUpJd6QFc1tqRi2tVI+Hrx7JC1Xzn+Y3JwyBKF0KUuhhNAbOtsTdJU/V8+Jh9m cajAuIWe9fV1j9qRTonjynh0MF8VCpmnyoM6djVI0NyLGiJOhaRO+kltK3C+jgwh w2LMpNGtFmuae8tk/426QsMmqhV4aJzs9mvIDFcN5TgH02pXA50gDkvEe4GwKhz1 SupKmEn+Als9AxSQKH6a9HjQMYRX5Uw4ekIR4vUoUQNLIBW7Ihq28BUCAwEAAaOB 2TCB1jAOBgNVHQ8BAf8EBAMCAQYwHQYDVR0OBBYEFIz02ZMKR7wAoErOS3VuoLaw sn78MB8GA1UdIwQYMBaAFMB6mGiNifurBWQMEX2qfWW4ysxOMBIGA1UdEwEB/wQI MAYBAf8CAQAwOgYDVR0fBDMwMTAvoC2gK4YpaHR0cDovL2NybC5nZW90cnVzdC5j b20vY3Jscy9ndGdsb2JhbC5jcmwwNAYIKwYBBQUHAQEEKDAmMCQGCCsGAQUFBzAB hhhodHRwOi8vb2NzcC5nZW90cnVzdC5jb20wDQYJKoZIhvcNAQEFBQADggEBADOR NxHbQPnejLICiHevYyHBrbAN+qB4VqOC/btJXxRtyNxflNoRZnwekcW22G1PqvK/ ISh+UqKSeAhhaSH+LeyCGIT0043FiruKzF3mo7bMbq1vsw5h7onOEzRPSVX1ObuZ lvD16lo8nBa9AlPwKg5BbuvvnvdwNs2AKnbIh+PrI7OWLOYdlF8cpOLNJDErBjgy YWE5XIlMSB1CyWee0r9Y9/k3MbBn3Y0mNhp4GgkZPJMHcCrhfCn13mZXCxJeFu1e vTezMGnGkqX2Gdgd+DYSuUuVlZzQzmwwpxb79k1ktl8qFJymyFWOIPllByTMOAVM IIi0tWeUz12OYjf+xLQ= -----END CERTIFICATE----- -----BEGIN CERTIFICATE----- MIIDVDCCAjygAwIBAgIDAjRWMA0GCSqGSIb3DQEBBQUAMEIxCzAJBgNVBAYTAlVT MRYwFAYDVQQKEw1HZW9UcnVzdCBJbmMuMRswGQYDVQQDExJHZW9UcnVzdCBHbG9i YWwgQ0EwHhcNMDIwNTIxMDQwMDAwWhcNMjIwNTIxMDQwMDAwWjBCMQswCQYDVQQG EwJVUzEWMBQGA1UEChMNR2VvVHJ1c3QgSW5jLjEbMBkGA1UEAxMSR2VvVHJ1c3Qg R2xvYmFsIENBMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA2swYYzD9 9BcjGlZ+W988bDjkcbd4kdS8odhM+KhDtgPpTSEHCIjaWC9mOSm9BXiLnTjoBbdq fnGk5sRgprDvgOSJKA+eJdbtg/OtppHHmMlCGDUUna2YRpIuT8rxh0PBFpVXLVDv iS2Aelet8u5fa9IAjbkU+BQVNdnARqN7csiRv8lVK83Qlz6cJmTM386DGXHKTubU 1XupGc1V3sjs0l44U+VcT4wt/lAjNvxm5suOpDkZALeVAjmRCw7+OC7RHQWa9k0+ bw8HHa8sHo9gOeL6NlMTOdReJivbPagUvTLrGAMoUgRx5aszPeE4uwc2hGKceeoW MPRfwCvocWvk+QIDAQABo1MwUTAPBgNVHRMBAf8EBTADAQH/MB0GA1UdDgQWBBTA ephojYn7qwVkDBF9qn1luMrMTjAfBgNVHSMEGDAWgBTAephojYn7qwVkDBF9qn1l uMrMTjANBgkqhkiG9w0BAQUFAAOCAQEANeMpauUvXVSOKVCUn5kaFOSPeCpilKIn Z57QzxpeR+nBsqTP3UEaBU6bS+5Kb1VSsyShNwrrZHYqLizz/Tt1kL/6cdjHPTfS tQWVYrmm3ok9Nns4d0iXrKYgjy6myQzCsplFAMfOEVEiIuCl6rYVSAlk6l5PdPcF PseKUgzbFbS9bZvlxrFUaKnjaZC2mqUPuLk/IH2uSrW4nOQdtqvmlKXBx4Ot2/Un hw4EbNX/3aBd7YdStysVAq45pmp06drE57xNNB6pXE0zX5IJL4hmXXeXxx12E6nV 5fEWCRE11azbJHFwLJhWC9kXtNHjUStedejV0NxPNO3CBWaAocvmMw== -----END CERTIFICATE----- `; // 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