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

/
/
gm

Test String

Code Generator

Language

Generated Code

const regex = /^(?<timestamp>\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\.\d{3}Z) (?<level>\w+) (?<servicename>(\w+|\-))\[(?<uniquething>[A-F\d]+)\] \[(?<function>Originator@\d+) sub=(?<subsys>\S+)\] (?<body>.*)$/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('^(?<timestamp>\\d{4}-\\d{2}-\\d{2}T\\d{2}:\\d{2}:\\d{2}\\.\\d{3}Z) (?<level>\\w+) (?<servicename>(\\w+|\\-))\\[(?<uniquething>[A-F\\d]+)\\] \\[(?<function>Originator@\\d+) sub=(?<subsys>\\S+)\\] (?<body>.*)$', 'gm') const str = `2017-05-04T14:46:44.163Z info vsansystem[7AFFC9DB20] [Originator@6876 sub=Default] Logging uses fast path: false 2017-05-04T14:46:45.163Z Section for PyVsanMOPropProvider, pid=68004, version=0.1, build=5310541, option=Release 2017-05-04T14:46:46Z mark: storage-path-claim-completed 2017-05-04T14:46:47.163Z verbose vsansystem[7AFFC9DB20] [Originator@6876 sub=Default] Dumping early logs: ------ Early init logs start -------- 2017-05-04T14:46:47.163Z info -[7AFFC9DB20] [Originator@6876 sub=Default] Glibc malloc guards disabled. 2017-05-04T14:46:47.163Z info -[7AFFC9DB20] [Originator@6876 sub=Default] Initialized SystemFactory ------ Early init logs end -------- 2017-05-04T14:46:47.163Z info vsansystem[7AFFC9DB20] [Originator@6876 sub=Default] Logging uses fast path: false 2017-05-04T14:46:47.163Z info vsansystem[7AFFC9DB20] [Originator@6876 sub=Default] The bora/lib logs WILL be handled by VmaCore 2017-05-04T14:46:47.163Z info vsansystem[7AFFC9DB20] [Originator@6876 sub=Default] Initialized channel manager 2017-05-04T14:46:47.163Z info vsansystem[7AFFC9DB20] [Originator@6876 sub=Default] Current working directory: /var/log/vmware 2017-05-04T14:46:47.163Z info vsansystem[7AFFC9DB20] [Originator@6876 sub=ThreadPool] Catch work item exceptions disabled. 2017-05-04T14:46:47.163Z info vsansystem[7AFFC9DB20] [Originator@6876 sub=FairScheduler] Priority level 4 is now active. 2017-05-04T14:46:47.163Z info vsansystem[7AFFC9DB20] [Originator@6876 sub=WorkQueue.vmacoreDefaultIOCompletionQueue] Created: WorkQueue.vmacoreDefaultIOCompletionQueue, type = fair, priority = 4 , itemWeight = 1 2017-05-04T14:46:47.163Z info vsansystem[7AFFC9DB20] [Originator@6876 sub=FairScheduler] Priority level 8 is now active. 2017-05-04T14:46:47.163Z info vsansystem[7AFFC9DB20] [Originator@6876 sub=WorkQueue.vmacoreDefaultIOQueue] Created: WorkQueue.vmacoreDefaultIOQueue, type = fair, priority = 8 , itemWeight = 1 2017-05-04T14:46:47.163Z info vsansystem[7AFFC9DB20] [Originator@6876 sub=FairScheduler] Priority level 16 is now active.`; // 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