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 = /Audit (?P<audit_outcome>Success|Failure),(?P<log_date>.*)\s+(?P<log_time>.*),Microsoft-Windows-Security-Auditing,(?P<event_id>\d+),(?P<category>.*),(?P<event_message>.*)\s+Subject:\s+Security ID:\s+(?P<subject_security_id>.*)\s+Account Name:\s+(?P<subject_account_name>.*)\s+Account Domain:\s+(?P<subject_account_domain>.*)\s+Logon ID:\s+(?P<subject_logon_id>.*)\s+Process Information:\s+Process ID:\s+(?P<PI_process_id>.*)\s+Name:\s+(?P<PI_name>.*)\s+Previous Time:\s+(?P<previous_time>.*)\s+New Time:\s+(?P<new_time>.*)\s+(?P<audit_message>.*)/g; // Alternative syntax using RegExp constructor // const regex = new RegExp('Audit (?P<audit_outcome>Success|Failure),(?P<log_date>.*)\\s+(?P<log_time>.*),Microsoft-Windows-Security-Auditing,(?P<event_id>\\d+),(?P<category>.*),(?P<event_message>.*)\\s+Subject:\\s+Security ID:\\s+(?P<subject_security_id>.*)\\s+Account Name:\\s+(?P<subject_account_name>.*)\\s+Account Domain:\\s+(?P<subject_account_domain>.*)\\s+Logon ID:\\s+(?P<subject_logon_id>.*)\\s+Process Information:\\s+Process ID:\\s+(?P<PI_process_id>.*)\\s+Name:\\s+(?P<PI_name>.*)\\s+Previous Time:\\s+(?P<previous_time>.*)\\s+New Time:\\s+(?P<new_time>.*)\\s+(?P<audit_message>.*)', 'g') const str = `Audit Success,29/08/2017 09:42:50,Microsoft-Windows-Security-Auditing,4616,Security State Change,"The system time was changed. Subject: Security ID: LOCAL SERVICE Account Name: LOCAL SERVICE Account Domain: NT AUTHORITY Logon ID: 0x3E5 Process Information: Process ID: 0x3e8 Name: C:\\Windows\\System32\\svchost.exe Previous Time: ‎2017‎-‎08‎-‎29T01:42:49.858143700Z New Time: ‎2017‎-‎08‎-‎29T01:42:49.520000000Z This event is generated when the system time is changed. It is normal for the Windows Time Service, which runs with System privilege, to change the system time on a regular basis. Other system time changes may be indicative of attempts to tamper with the computer."`; // 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