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

/
/

Test String

Code Generator

Language

Generated Code

use strict; my $str = 'May 30 11:56:03 10.10.0.1 May 30 11:56:04 HappyMK Accept forward: in:bridge-vlan11 out:ether1-gateway, src-mac 60:c5:47:09:bd:c8, proto TCP (SYN), 10.11.0.251:58615->17.134.126.209:443, prio 1->0, len 64 May 30 11:55:29 10.10.0.1 May 30 11:55:29 HappyMK Accept forward: in:vlan10 out:ether1-gateway, src-mac 00:60:6e:a5:61:c1, proto UDP, 10.10.0.14:62164->157.56.106.184:3544, NAT (10.10.0.14:62164->89.141.65.84:62164)->157.56.106.184:3544, len 84 May 30 11:56:25 10.10.0.1 May 30 11:56:26 HappyMK Accept forward: in:vlan10 out:ether1-gateway, src-mac 00:60:6e:a5:61:c1, proto UDP, 10.10.0.14:62164->157.56.106.189:3544, len 84 '; my $regex = qr/.+HappyMK\s?(?<action>\S+)\s(?<chain>\w+):\sin:(?<int_in>\S+)\sout:(?<int_out>\S+), src-mac\s(?<src_mac>\S+),\sproto\s(?<prot>\w+)(\s(?<flags>\S+),|,)\s(?<src_ip>\b(?:\d{1,3}\.){3}\d{1,3}\b):(?<src_port>\d+)->(?<dest_ip>\b(?:\d{1,3}\.){3}\d{1,3}\b):(?<dest_port>\d+),(\s(?<NAT>\w+)\s\((?<src_nat_localip>\b(?:\d{1,3}\.){3}\d{1,3}\b):(?<src_nat_local_port>\d+)->(?<src_nat_public_ip>\b(?:\d{1,3}\.){3}\d{1,3}\b):(?<src_nat_public_port>\d+)\)->(?<dest_nat_ip>\b(?:\d{1,3}\.){3}\d{1,3}\b):(?<dest_nat_port>\d+),)?(\sprio\s(?<prio>\d+->\d+),)?\slen\s(?<len>\d+)/p; if ( $str =~ /$regex/ ) { 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