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

package main import ( "regexp" "fmt" ) func main() { var re = regexp.MustCompile(`(?m)ENV GOSS_VERSION="(?<currentValue>.*)"`) var 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." ` for i, match := range re.FindAllString(str, -1) { fmt.Println(match, "found at index", i) } }

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 Golang, please visit: https://golang.org/pkg/regexp/