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 = /^.*?Dropping SNMP request from 10\.57\.0\.42.*to outside.*$|^.*?Source=VLAN1108_10\.57\.98\.(238|239).*Destination=VLAN406_10\.57\.227\.(51|52).*rule_name=NetBackup Access.*$/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('^.*?Dropping SNMP request from 10\\.57\\.0\\.42.*to outside.*$|^.*?Source=VLAN1108_10\\.57\\.98\\.(238|239).*Destination=VLAN406_10\\.57\\.227\\.(51|52).*rule_name=NetBackup Access.*$', 'gm') const str = `<Event xmlns='http://schemas.microsoft.com/win/2004/08/events/event'><System><Provider Name='AD FS' Guid='{2ffb687a-1571-4ace-8550-47ab5ccae2bc}'/><EventID>325</EventID><Version>0</Version><Level>Error</Level><Task>None</Task><Opcode>Info</Opcode><Keywords>AD FS</Keywords><TimeCreated SystemTime='2019-06-04T12:20:06.108450100Z'/><EventRecordID>4031017</EventRecordID><Correlation ActivityID='{00000000-0000-0000-2d5d-0080000000cd}'/><Execution ProcessID='3760' ThreadID='6728'/><Channel>AD FS/Admin</Channel><Computer>GIG06SRVADFS001.cymru.nhs.uk</Computer><Security UserID='CYMRU\\GIG_gMSA_ADFS\$'/></System><UserData>The Federation Service could not authorize token issuance for caller 'CYMRU\\Ma047550 '. The caller is not authorized to request a token for the relying party 'urn:federation:MicrosoftOnline'. See event 501 with the same Instance ID for caller identity. Additional Data Instance ID: 807cd7c3-c574-4703-b8e4-cbf8a7102bca Relying party: urn:federation:MicrosoftOnline Exception details: Microsoft.IdentityServer.Service.IssuancePipeline.CallerAuthorizationException: MSIS5007: The caller authorization failed for caller identity CYMRU\\Ma047550 for relying party trust urn:federation:MicrosoftOnline. at Microsoft.IdentityModel.Threading.AsyncResult.End(IAsyncResult result) at Microsoft.IdentityModel.Protocols.WSTrust.WSTrustServiceContract.ProcessCoreAsyncResult.End(IAsyncResult ar) at Microsoft.IdentityModel.Protocols.WSTrust.WSTrustServiceContract.EndProcessCore(IAsyncResult ar, String requestAction, String responseAction, String trustNamespace) User Action Use the AD FS Management snap-in to ensure that the caller is authorized to request a token for the relying party.</UserData></Event>​ `; // 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