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
Processing...

Test String

Code Generator

Language

Generated Code

const regex = /^<.{20}(?<hlt_env>.+?) esc-logs/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('^<.{20}(?<hlt_env>.+?) esc-logs', 'gm') const str = `<13>Jan. 05 23:59:59 HLT-DM01 esc-logs[-]: {"timestamp":"2021-01-05T23:59:59.889Z","id":"98cf03ff-8dba-4b84-990c-4f026a2fa942","tenant_name":"draco-910","pks_uuid":"934ac265-9e3c-4a0d-8798-109b15876e4e","hlt-cluster":["api.prod-s-k8s.draco-910.sccloudres.net","api.prod-m-k8s.draco-910.sccloudres.net"],"log_type":"AUDIT","log_entry":"<14>1 2021-01-05T23:59:59.889967Z 682e85b4-e773-4ef7-9c8b-193034f2eca9.master.pks-934ac265-9e3c-4a0d-8798-109b15876e4e.service-instance-934ac265-9e3c-4a0d-8798-109b15876e4e.bosh kube-apiserver rs2 - [instance@47450 director=\\"\\" deployment=\\"service-instance_934ac265-9e3c-4a0d-8798-109b15876e4e\\" group=\\"master\\" az=\\"WL-BEW-Prd-01\\" id=\\"682e85b4-e773-4ef7-9c8b-193034f2eca9\\"] {\\"kind\\":\\"Event\\",\\"apiVersion\\":\\"audit.k8s.io/v1\\",\\"level\\":\\"Request\\",\\"auditID\\":\\"b3b53fd5-4d9d-4626-90bb-ac0de8234585\\",\\"stage\\":\\"ResponseComplete\\",\\"requestURI\\":\\"/api/v1/nodes/321c1ee3-21ba-43e1-8c5f-4b73a30d111c/proxy/metrics\\",\\"verb\\":\\"get\\",\\"user\\":{\\"username\\":\\"system:serviceaccount:monitoring:prometheus-monitoring\\",\\"uid\\":\\"abb07484-47d5-462c-b460-682dd0c0768d\\",\\"groups\\":[\\"system:serviceaccounts\\",\\"system:serviceaccounts:monitoring\\",\\"system:authenticated\\"]},\\"sourceIPs\\":[\\"11.32.19.6\\"],\\"userAgent\\":\\"Prometheus/2.19.3\\",\\"objectRef\\":{\\"resource\\":\\"nodes\\",\\"name\\":\\"321c1ee3-21ba-43e1-8c5f-4b73a30d111c\\",\\"apiVersion\\":\\"v1\\",\\"subresource\\":\\"proxy\\"},\\"responseStatus\\":{\\"metadata\\":{},\\"code\\":200},\\"requestReceivedTimestamp\\":\\"2021-01-05T23:59:59.434872Z\\",\\"stageTimestamp\\":\\"2021-01-05T23:59:59.456258Z\\",\\"annotations\\":{\\"authorization.k8s.io/decision\\":\\"allow\\",\\"authorization.k8s.io/reason\\":\\"RBAC: allowed by ClusterRoleBinding \\\\\\"prometheus-monitoring\\\\\\" of ClusterRole \\\\\\"prometheus-monitoring\\\\\\" to ServiceAccount \\\\\\"prometheus-monitoring/monitoring\\\\\\"\\"}}","version":"1.0","@version":"1","cloud_service_name":"KUBERNETES","@timestamp":"2021-01-05T23:59:59.889Z"} `; // 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