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

/
/
sxXg

Test String

Code Generator

Language

Generated Code

use strict; my $str = 'Valid 192.168.1.1 192.168.255.255 Invalid 0.0.0.0 0.0.0.1 0.0.0.255 1.0.0.255 '; my $regex = qr/#IPv4 (?<IPv4> (?!0+\.) (?<byte>2(?:[0-4]\d|5[0-5])|1?\d{1,2}) (?:\.(?&byte)){3} ) #IPv6 from http://vernon.mauery.com/content/projects/linux/ipv6_regex | (?<smb>[0-9a-f]{1,4}:){1,1} (?<sme>:[0-9a-f]{1,4}){1,6} | (?&smb){1,2} (?&sme){1,5} | (?&smb){1,3} (?&sme){1,4} | (?&smb){1,4} (?&sme){1,3} | (?&smb){1,5} (?&sme){1,2} | (?&smb){1,6} (?&sme){1,1} | ((?&smb){1,7}|:): | :(?&sme){1,7} | (?&smb){6} (?&IPv4) | (?&smb){5} :?+ [0-9a-f]{1,4} :(?&IPv4) | (?&smb){1,1} (?&sme){1,4} :(?&IPv4) | (?&smb){1,2} (?&sme){1,3} :(?&IPv4) | (?&smb){1,3} (?&sme){1,2} :(?&IPv4) | (?&smb){1,4} (?&sme){1,1} :(?&IPv4) | ((?&smb){1,5}|:) :(?&IPv4) | :(?&sme){1,5} :(?&IPv4) /sxp; 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