Regular Expressions 101

Save & Share

Flavor

  • PCRE2 (PHP >=7.3)
  • PCRE (PHP <7.3)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java 8
  • .NET 7.0 (C#)
  • Rust
  • Regex Flavor Guide

Function

  • Match
  • Substitution
  • List
  • Unit Tests

Tools

Sponsors
There are currently no sponsors. Become a sponsor today!
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
  • Match everything enclosed
    (?:...)
  • Capture everything enclosed
    (...)
  • 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

$re = '/^(?<time>\w{3} \d{2}, \d{4} \d{2}:\d{2}:\d{2} \w[AM|PM]) (?<thread>.*)/m'; $str = '2013-3-03 14:27:33 [main] INFO Main - Start 2013-3-03 14:27:33 [main] ERROR Main - Exception javax.management.RuntimeErrorException: null at Main.main(Main.java:16) ~[bin/:na] 2013-3-03 14:27:33 [main] INFO Main - End Feb 06, 2019 10:46:27 AM hudson.model.ParametersAction filter WARNING: Skipped parameter `STABLE_RELEASE` as it is undefined on `AUTOMATEDTEST/ENT/atb-ent-api-etransfersenderprofile-automation_qa`. Set `-Dhudson.model.ParametersAction.keepUndefinedPara meters=true` to allow undefined parameters to be injected as environment variables or `-Dhudson.model.ParametersAction.safeParameters=[comma-separated list]` to whitelist specific parameter names, even though it represents a security breach or `-Dhudson.model.ParametersAction.keepUndefinedParameters=false` to no longer show this message. Feb 06, 2019 11:28:46 AM org.eclipse.jetty.server.handler.ContextHandler$Context log WARNING: Error while serving https://jenkins-master.pipeline.atb.com/securityRealm/finishLogin java.lang.reflect.InvocationTargetException at org.kohsuke.stapler.Function$MethodFunction.invoke(Function.java:347) at org.kohsuke.stapler.interceptor.RequirePOST$Processor.invoke(RequirePOST.java:77) at org.kohsuke.stapler.PreInvokeInterceptedFunction.invoke(PreInvokeInterceptedFunction.java:26) at org.kohsuke.stapler.Function.bindAndInvoke(Function.java:184) at org.kohsuke.stapler.Function.bindAndInvokeAndServeResponse(Function.java:117) at org.kohsuke.stapler.MetaClass$1.doDispatch(MetaClass.java:129) at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:58) at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:734) at org.kohsuke.stapler.Stapler.invoke(Stapler.java:864) at org.kohsuke.stapler.MetaClass$3.doDispatch(MetaClass.java:209) at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:58) at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:734) at org.kohsuke.stapler.Stapler.invoke(Stapler.java:864) at org.kohsuke.stapler.Stapler.invoke(Stapler.java:668) at org.kohsuke.stapler.Stapler.service(Stapler.java:238) at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:865) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1655) at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:154) at org.jenkinsci.plugins.ssegateway.Endpoint$SSEListenChannelFilter.doFilter(Endpoint.java:243) at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:151) at io.jenkins.blueocean.ResourceCacheControl.doFilter(ResourceCacheControl.java:134) at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:151) at io.jenkins.blueocean.auth.jwt.impl.JwtAuthenticationFilter.doFilter(JwtAuthenticationFilter.java:61) at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:151) at net.bull.javamelody.MonitoringFilter.doFilter(MonitoringFilter.java:239) at net.bull.javamelody.MonitoringFilter.doFilter(MonitoringFilter.java:215) at net.bull.javamelody.PluginMonitoringFilter.doFilter(PluginMonitoringFilter.java:88) at org.jvnet.hudson.plugins.monitoring.HudsonMonitoringFilter.doFilter(HudsonMonitoringFilter.java:114) at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:151) at jenkins.metrics.impl.MetricsFilter.doFilter(MetricsFilter.java:125) at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:151) at hudson.plugins.greenballs.GreenBallFilter.doFilter(GreenBallFilter.java:59) at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:151) at hudson.util.PluginServletFilter.doFilter(PluginServletFilter.java:157) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) at org.jenkinsci.plugins.saml.SamlCrumbExclusion.process(SamlCrumbExclusion.java:26) at hudson.security.csrf.CrumbFilter.doFilter(CrumbFilter.java:73) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:84) at hudson.security.UnwrapSecurityExceptionFilter.doFilter(UnwrapSecurityExceptionFilter.java:51) at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87) at jenkins.security.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:117) at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87) at org.acegisecurity.providers.anonymous.AnonymousProcessingFilter.doFilter(AnonymousProcessingFilter.java:125) at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87) at org.acegisecurity.ui.rememberme.RememberMeProcessingFilter.doFilter(RememberMeProcessingFilter.java:135) at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87) at org.acegisecurity.ui.AbstractProcessingFilter.doFilter(AbstractProcessingFilter.java:271) at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87) at jenkins.security.BasicHeaderProcessor.doFilter(BasicHeaderProcessor.java:93) at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87) at org.acegisecurity.context.HttpSessionContextIntegrationFilter.doFilter(HttpSessionContextIntegrationFilter.java:249) at hudson.security.HttpSessionContextIntegrationFilter2.doFilter(HttpSessionContextIntegrationFilter2.java:67) at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87) at hudson.security.ChainedServletFilter.doFilter(ChainedServletFilter.java:90) at hudson.security.HudsonFilter.doFilter(HudsonFilter.java:171) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) at org.kohsuke.stapler.compression.CompressionFilter.doFilter(CompressionFilter.java:49) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) at hudson.util.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:82) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) at org.kohsuke.stapler.DiagnosticThreadNameFilter.doFilter(DiagnosticThreadNameFilter.java:30) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:533) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:146) at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:524) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:257) at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1595) at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:255) at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1317) at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:203) at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:473) at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1564) at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:201) at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1219) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:144) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) at org.eclipse.jetty.server.Server.handle(Server.java:531) at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:352) at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:260) at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:281) at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:102) at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:118) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:333) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:310) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:168) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:126) at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:366) at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:762) at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:680) at java.lang.Thread.run(Thread.java:748) Caused by: org.acegisecurity.BadCredentialsException: Response issue instant is too old or in the future; nested exception is org.pac4j.saml.exceptions.SAMLException: Response issue instant is too old or in the future at org.jenkinsci.plugins.saml.SamlProfileWrapper.process(SamlProfileWrapper.java:59) at org.jenkinsci.plugins.saml.SamlProfileWrapper.process(SamlProfileWrapper.java:35) at org.jenkinsci.plugins.saml.OpenSAMLWrapper.get(OpenSAMLWrapper.java:64) at org.jenkinsci.plugins.saml.SamlSecurityRealm.doFinishLogin(SamlSecurityRealm.java:304) at java.lang.invoke.MethodHandle.invokeWithArguments(MethodHandle.java:627) at org.kohsuke.stapler.Function$MethodFunction.invoke(Function.java:343) ... 92 more Caused by: org.pac4j.saml.exceptions.SAMLException: Response issue instant is too old or in the future at org.pac4j.saml.sso.impl.SAML2DefaultResponseValidator.validateSamlProtocolResponse(SAML2DefaultResponseValidator.java:218) at org.pac4j.saml.sso.impl.SAML2DefaultResponseValidator.validate(SAML2DefaultResponseValidator.java:132) at org.pac4j.saml.sso.impl.SAML2WebSSOMessageReceiver.receiveMessage(SAML2WebSSOMessageReceiver.java:77) at org.pac4j.saml.sso.impl.SAML2WebSSOProfileHandler.receive(SAML2WebSSOProfileHandler.java:35) at org.pac4j.saml.client.SAML2Client.retrieveCredentials(SAML2Client.java:225) at org.pac4j.saml.client.SAML2Client.retrieveCredentials(SAML2Client.java:60) at org.pac4j.core.client.IndirectClient.getCredentials(IndirectClient.java:106) at org.jenkinsci.plugins.saml.SamlProfileWrapper.process(SamlProfileWrapper.java:55) ... 97 more '; preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0); // Print the entire match result var_dump($matches);

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 PHP, please visit: http://php.net/manual/en/ref.pcre.php