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>\w+ \d+ \d+:\d+:\d*)\s+(?<servername>\w+)[^\[]+\[(?<log_level>[^\]]+)\][^\]]+\]\s+(?<message>.*)/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('^(?<timestamp>\\w+ \\d+ \\d+:\\d+:\\d*)\\s+(?<servername>\\w+)[^\\[]+\\[(?<log_level>[^\\]]+)\\][^\\]]+\\]\\s+(?<message>.*)', 'gm') const str = `Jan 3 03:50:38 xtestf100s goferd: [INFO][worker-0] gofer.messaging.adapter.connect:28 - connecting: proton+amqps://xtest123s.pharma.aventis.com:5647 Jan 3 03:50:38 xtestf100s goferd: [INFO][worker-0] gofer.messaging.adapter.proton.connection:87 - open: URL: amqps://xtest123s.pharma.aventis.com:5647|SSL: ca: /etc/rhsm/ca/katello-default-ca.pem|key: None|certificate: /etc/pki/consumer/bundle.pem|host-validation: None Jan 3 03:50:38 xtestf100s goferd: [ERROR][worker-0] gofer.messaging.adapter.connect:33 - connect: proton+amqps://xtest123s.pharma.aventis.com:5647, failed: Connection amqps://xtest123s.pharma.aventis.com:5647 disconnected: Condition('proton.pythonio', 'Connection refused to all addresses') Jan 3 03:50:38 xtestf100s goferd: [INFO][worker-0] gofer.messaging.adapter.connect:35 - retry in 106 seconds Jan 3 03:50:54 xtestf100s kernel: type=1400 audit(1672714254.276:566412): avc: denied { read } for pid=75981 comm="ip" name="libCvDllFilter.so" dev="dm-13" ino=393745 scontext=system_u:system_r:ifconfig_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=file permissive=1 Jan 3 03:50:54 xtestf100s kernel: type=1400 audit(1672714254.276:566413): avc: denied { open } for pid=75981 comm="ip" path="/opt/commvault/Base64/libCvDllFilter.so" dev="dm-13" ino=393745 scontext=system_u:system_r:ifconfig_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=file permissive=1 Jan 3 03:50:54 xtestf100s kernel: type=1400 audit(1672714254.276:566414): avc: denied { getattr } for pid=75981 comm="ip" path="/opt/commvault/Base64/libCvDllFilter.so" dev="dm-13" ino=393745 scontext=system_u:system_r:ifconfig_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=file permissive=1 Jan 3 03:50:54 xtestf100s kernel: type=1400 audit(1672714254.276:566415): avc: denied { execute } for pid=75981 comm="ip" path="/opt/commvault/Base64/libCvDllFilter.so" dev="dm-13" ino=393745 scontext=system_u:system_r:ifconfig_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=file permissive=1 Jan 3 03:51:43 xtestf100s kernel: type=1400 audit(1672714303.392:566416): avc: denied { read } for pid=77988 comm="ip" name="Base" dev="dm-13" ino=116 scontext=system_u:system_r:ifconfig_t:s0 tcontext=unconfined_u:object_r:unlabeled_t:s0 tclass=lnk_file permissive=1 Jan 3 03:51:43 xtestf100s kernel: type=1400 audit(1672714303.392:566417): avc: denied { read } for pid=77988 comm="ip" name="libCvDllFilter.so" dev="dm-13" ino=393745 scontext=system_u:system_r:ifconfig_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=file permissive=1`; // 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