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 = "^(?<exe>npm)?\\ ?(?<run>(?<=\\k<exe> )run(?:-script)?)?\\ ?(?<command>(?<=\\k<run> )[a-z]+(?:[-|:|.|_][a-z]+)?|(?<!\\k<run> )[a-z]+(?:[-][a-z]+)?)?\\ ?(?<pkgdetails>[a-z0-9\\>\\=\\:\\+\\#\\^\\.\\@\\/][a-z0-9\\>\\=\\:\\+\\#\\^\\~\\.\\@\\/\\-]+)?\\ ?(?<options>(?:\\ [-]{1,2}[a-zA-Z]+(?:[-][a-z]+)*)*)?$"; final String string = "npm install cordova-browser@~5.0.1 --production --save\n\n" + "npm install --no-package-lock\n" + "npm -v\n\n" + "npm version major\n" + "npm version minor\n" + "npm version patch\n\n" + "npm run build\n" + "npm run build:spypkg\n" + "npm run build-spypkg\n" + "npm run build.spypkg\n" + "npm run build_spypkg\n" + "npm run-script build:spypkg\n" + "npm run-script build-spypkg\n" + "npm run-script build.spypkg\n" + "npm run-script build_spypkg\n\n" + "i sots --D\n" + "i sots --production\n" + "i sots --production --no-save\n" + "install sots --production --no-save\n" + "npm install sots --production --no-save\n\n" + "npm install ./package.tgz\n" + "npm install https://github.com/indexzero/forever/tarball/v0.5.6\n" + "npm install sax\n" + "npm install sax -P\n" + "npm install sax -D\n" + "npm install sax -O\n\n" + "i\n\n" + "npm i\n" + "i sax\n" + "i sax -D\n" + "install\n" + "install sax -P\n" + "install sax -D\n" + "install sax -O\n" + "npm install githubname/reponame\n" + "npm install @myorg/privatepackage\n" + "npm install node-tap --save-dev\n" + "npm install dtrace-provider --save-optional\n" + "npm install readable-stream --save-exact\n" + "npm install ansi-regex --save-bundle\n" + "npm install sax@latest\n" + "npm install @myorg/mypackage@latest\n" + "npm install sax@0.1.1\n" + "npm install @myorg/privatepackage@1.5.0\n" + "npm install sax@\">=0.1.0 <0.2.0\"\n" + "npm install @myorg/privatepackage@\">=0.1.0 <0.2.0\"\n" + "npm install git+ssh://git@github.com:npm/cli.git#v1.0.27\n" + "npm install git+ssh://git@github.com:npm/cli#semver:^5.0\n" + "npm install git+https://isaacs@github.com/npm/cli.git\n" + "npm install git://github.com/npm/cli.git#v1.0.27\n" + "npm install mygithubuser/myproject\n" + "npm install github:mygithubuser/myproject\n" + "npm install gist:101a11beef\n" + "npm install bitbucket:mybitbucketuser/myproject\n" + "npm install gitlab:mygitlabuser/myproject\n" + "npm install gitlab:myusr/myproj#semver:^5.0\n" + "npm install sax@\">=0.1.0 <0.2.0\" bench supervisor\n" + "npm install sax --force"; 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