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
  • 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

/
/
gmi

Test String

Code Generator

Generated Code

use strict; my $str = '[14:41:43] [Server thread/INFO] [journeymap]: meaneea joining dimension -1 [14:41:43] [Server thread/INFO] [Mekanism]: Sent config to \'meaneea.\' [14:41:43] [Server thread/ERROR] [FML]: FMLIndexedMessageCodec exception caught io.netty.handler.codec.EncoderException: java.lang.RuntimeException: Undefined discriminator for message type com.github.lunatrius.ingameinfo.network.message.MessageSeed in channel ingameinfoxml at io.netty.handler.codec.MessageToMessageEncoder.write(MessageToMessageEncoder.java:106) ~[minecraft_server.1.12.2.jar:?] at io.netty.handler.codec.MessageToMessageCodec.write(MessageToMessageCodec.java:116) ~[minecraft_server.1.12.2.jar:?] at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:738) ~[minecraft_server.1.12.2.jar:?] at io.netty.channel.AbstractChannelHandlerContext.invokeWriteAndFlush(AbstractChannelHandlerContext.java:801) ~[minecraft_server.1.12.2.jar:?] at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:814) ~[minecraft_server.1.12.2.jar:?] at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:794) ~[minecraft_server.1.12.2.jar:?] at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:831) ~[minecraft_server.1.12.2.jar:?] at io.netty.channel.DefaultChannelPipeline.writeAndFlush(DefaultChannelPipeline.java:1032) ~[minecraft_server.1.12.2.jar:?] at io.netty.channel.AbstractChannel.writeAndFlush(AbstractChannel.java:296) ~[minecraft_server.1.12.2.jar:?] at net.minecraftforge.fml.common.network.simpleimpl.SimpleNetworkWrapper.sendTo(SimpleNetworkWrapper.java:250) [SimpleNetworkWrapper.class:?] at com.github.lunatrius.ingameinfo.handler.PlayerHandler.onPlayerLogin(PlayerHandler.java:15) [PlayerHandler.class:?] at net.minecraftforge.fml.common.eventhandler.ASMEventHandler_564_PlayerHandler_onPlayerLogin_PlayerLoggedInEvent.invoke(.dynamic) [?:?] at net.minecraftforge.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:90) [ASMEventHandler.class:?] at net.minecraftforge.fml.common.eventhandler.EventBus.post(EventBus.java:182) [EventBus.class:?] at net.minecraftforge.fml.common.FMLCommonHandler.firePlayerLoggedIn(FMLCommonHandler.java:575) [FMLCommonHandler.class:?] at net.minecraft.server.management.PlayerList.initializeConnectionToPlayer(PlayerList.java:219) [pl.class:?] at shadows.fastbench.net.HijackedDedicatedPlayerList.initializeConnectionToPlayer(HijackedDedicatedPlayerList.java:19) [HijackedDedicatedPlayerList.class:?] at net.minecraftforge.fml.common.network.handshake.NetworkDispatcher.completeServerSideConnection(NetworkDispatcher.java:255) [NetworkDispatcher.class:?] at net.minecraftforge.fml.common.network.handshake.NetworkDispatcher.access$100(NetworkDispatcher.java:72) [NetworkDispatcher.class:?] at net.minecraftforge.fml.common.network.handshake.NetworkDispatcher$1.func_73660_a(NetworkDispatcher.java:205) [NetworkDispatcher$1.class:?] at net.minecraft.network.NetworkManager.func_74428_b(NetworkManager.java:285) [gw.class:?] at net.minecraft.network.NetworkSystem.func_151269_c(NetworkSystem.java:180) [oz.class:?] at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:790) [MinecraftServer.class:?] at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:397) [nz.class:?] at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:668) [MinecraftServer.class:?] at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:526) [MinecraftServer.class:?] at java.lang.Thread.run(Unknown Source) [?:1.8.0_291] Caused by: java.lang.RuntimeException: Undefined discriminator for message type com.github.lunatrius.ingameinfo.network.message.MessageSeed in channel ingameinfoxml at net.minecraftforge.fml.common.network.FMLIndexedMessageToMessageCodec.encode(FMLIndexedMessageToMessageCodec.java:76) ~[FMLIndexedMessageToMessageCodec.class:?] at io.netty.handler.codec.MessageToMessageCodec$1.encode(MessageToMessageCodec.java:67) ~[minecraft_server.1.12.2.jar:?] at io.netty.handler.codec.MessageToMessageEncoder.write(MessageToMessageEncoder.java:88) ~[minecraft_server.1.12.2.jar:?] ... 26 more [14:41:43] [Server thread/INFO] [journeymap]: Sending log in packet. [14:41:43] [Server thread/INFO] [ViesCraft]: Logged in Server [14:45:07] [Server thread/INFO] [journeymap]: meaneea joining dimension 0 [14:45:08] [Server thread/INFO] [FML]: Unloading dimension -1'; my $regex = qr/\[(\d{2}:\d{2}:\d{2})] \[(.*)\/(INFO|WARN|ERROR|FATAL)]( \[.*])*:((?:.*\n(?!\[\d{2}:\d{2}:\d{2}]))*.*)/mip; if ( $str =~ /$regex/g ) { print "Whole match is ${^MATCH} and its start/end positions can be obtained via \$-[0] and \$+[0]\n"; # print "Capture Group 1 is $1 and its start/end positions can be obtained via \$-[1] and \$+[1]\n"; # print "Capture Group 2 is $2 ... and so on\n"; } # ${^POSTMATCH} and ${^PREMATCH} are also available with the use of '/p' # Named capture groups can be called via $+{name}

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 Perl, please visit: http://perldoc.perl.org/perlre.html