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

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "ENV GOSS_VERSION=\"(?<currentValue>.*)\""; final String string = "FROM kudobuilder/kuttl:v0.15.0\n\n" + "ENV GOSS_VERSION=\"v0.3.20\"\n" + "ENV KUTTL_VERSION=\"v0.44.0\"\n\n" + "# curl -LO https://storage.googleapis.com/kubernetes-release/release/v1.26.0/bin/linux/amd64/kubectl && \\\n" + "# chmod +x ./kubectl && \\\n" + "# mv ./kubectl /usr/local/bin/kubectl && \\\n\n\n" + "# Pending merge of https://github.com/goss-org/goss/pull/792 and https://github.com/kudobuilder/kuttl/pull/448\n" + "RUN echo \"Installing carvel ytt version ${KUTTL_VERSION}\" ; \\\n" + " curl -L \"https://github.com/goss-org/goss/releases/download/${KUTTL_VERSION}/ytt-linux-amd64\" -o /usr/local/bin/ytt && \\\n" + " chmod +rx /usr/local/bin/ytt && \\\n" + " echo \"Installing goss and kgoss version ${GOSS_VERSION}\" ; \\\n" + " curl -L \"https://github.com/goss-org/goss/releases/download/${GOSS_VERSION}/goss-linux-amd64\" -o /usr/local/bin/goss && \\\n" + " chmod +rx /usr/local/bin/goss && \\\n" + " curl -LO https://raw.githubusercontent.com/orange-cloudfoundry/goss/kgoss-kubectl-opts/extras/kgoss/kgoss -o /usr/local/bin/kgoss && \\\n" + " chmod +rx /usr/local/bin/kgoss && \\\n" + " /usr/local/bin/ytt --version && \\\n" + " /usr/local/bin/goss -v && \\\n" + " /usr/local/bin/kubectl version && \\\n" + " /usr/local/bin/kgoss || echo \"Installation done.\"\n\n"; final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE); final Matcher matcher = pattern.matcher(string); while (matcher.find()) { System.out.println("Full match: " + matcher.group(0)); for (int i = 1; i <= matcher.groupCount(); i++) { System.out.println("Group " + i + ": " + matcher.group(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 Java, please visit: https://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html