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 = /ENV GOSS_VERSION="(?<currentValue>.*)"/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('ENV GOSS_VERSION="(?<currentValue>.*)"', 'gm') const str = `FROM kudobuilder/kuttl:v0.15.0 ENV GOSS_VERSION="v0.3.20" ENV KUTTL_VERSION="v0.44.0" # curl -LO https://storage.googleapis.com/kubernetes-release/release/v1.26.0/bin/linux/amd64/kubectl && \\ # chmod +x ./kubectl && \\ # mv ./kubectl /usr/local/bin/kubectl && \\ # Pending merge of https://github.com/goss-org/goss/pull/792 and https://github.com/kudobuilder/kuttl/pull/448 RUN echo "Installing carvel ytt version \${KUTTL_VERSION}" ; \\ curl -L "https://github.com/goss-org/goss/releases/download/\${KUTTL_VERSION}/ytt-linux-amd64" -o /usr/local/bin/ytt && \\ chmod +rx /usr/local/bin/ytt && \\ echo "Installing goss and kgoss version \${GOSS_VERSION}" ; \\ curl -L "https://github.com/goss-org/goss/releases/download/\${GOSS_VERSION}/goss-linux-amd64" -o /usr/local/bin/goss && \\ chmod +rx /usr/local/bin/goss && \\ curl -LO https://raw.githubusercontent.com/orange-cloudfoundry/goss/kgoss-kubectl-opts/extras/kgoss/kgoss -o /usr/local/bin/kgoss && \\ chmod +rx /usr/local/bin/kgoss && \\ /usr/local/bin/ytt --version && \\ /usr/local/bin/goss -v && \\ /usr/local/bin/kubectl version && \\ /usr/local/bin/kgoss || echo "Installation done." `; // 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