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

/
/
s

Test String

Code Generator

Language

Generated Code

const regex = /(?(DEFINE)(?'value'(?:\N*(?:\n(?:(?: {8}|\t)\N*))*)))\s*pool: (?'pool'\g'value')\n\s*state: (?'state'\g'value')\n((?:\s*status: (?'status'\g'value')\n)?(?:\s*action: (?'action'\g'value')\n)?\s*scan: (?'scan'\g'value')\n)?\s*config:\n\n(?'config'\g'value')\n\s*errors: (?'errors'\g'value')/s; // Alternative syntax using RegExp constructor // const regex = new RegExp('(?(DEFINE)(?\'value\'(?:\\N*(?:\\n(?:(?: {8}|\\t)\\N*))*)))\\s*pool: (?\'pool\'\\g\'value\')\\n\\s*state: (?\'state\'\\g\'value\')\\n((?:\\s*status: (?\'status\'\\g\'value\')\\n)?(?:\\s*action: (?\'action\'\\g\'value\')\\n)?\\s*scan: (?\'scan\'\\g\'value\')\\n)?\\s*config:\\n\\n(?\'config\'\\g\'value\')\\n\\s*errors: (?\'errors\'\\g\'value\')', 's') const str = ` pool: zfs state: ONLINE config: NAME STATE READ WRITE CKSUM zfs ONLINE 0 0 0 ata-HGST_HTS725050A7E630_TF655AY92LL99L ONLINE 0 0 0 errors: No known data errors`; // Reset `lastIndex` if this regex is defined globally // regex.lastIndex = 0; let m; if ((m = regex.exec(str)) !== null) { // 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