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
Processing...

Test String

Code Generator

Language

Generated Code

use strict; my $str = 'false_positive=do+you+want+a+pizza?+with+mozzarella/pomodoro? host=www.google.com;cd+/etc;/bin$u/ca*+passwd host=www.google.com;cat$@/etc$@/passwd host=www.google.com;cd+/et*;/bi*$u/ca*+passwd host=www.google.it;/bin/c*t$u+/etc$u/passwd host=www.google.it;/bin/cat$u+/*tc$u/passwd host=www.google.it;cd+/etc;/bin/c*t+passwd host=www.google.com;/bin/ca?+/et?/passwd host=www.google.com;cat+/etc/${a}passwd host=www.google.com;cat+/etc/$(echo)passwd host=www.google.com;cat+/etc/`echo`passwd host=www.google.com;cat+/etc${a}/passwd host=www.google.com;cat+/etc$(echo)/passwd host=www.google.com;cat+/etc`echo`/passwd host=www.google.com;cat+/etc/passwd${a} host=www.google.com;cat+/etc/passwd$(echo) host=www.google.com;cat+/etc/passwd`echo` host=www.google.com;ca?+/et?/pa??wd host=www.google.com;cd+etc/+ca?+passwd host=www.google.com;?at+/?tc/passwd host=www.google.com;c\\a\\t+/e\\t\\c/pa\\s\\swd host=www.google.com;cd+/etc;c\\at+p\\a\\sswd host=www.google.com;cd+/etc;c\'at\'+p\'a\'sswd host=www.google.com;c$@at /et$@c/pas$@swd host=www.google.com;c$!at /et$!c/pas$!swd host=www.google.com;c$*at /et$*c/pas$*swd host=www.google.com;c$?at /et$?c/pas$?swd host=www.google.com;c$-at /et$-c/pas$-swd host=www.google.com;c$_at /et$_c/pas$_swd host=www.google.com;c$$at /et$$c/pas$$swd'; my $regex = qr/(?:['\*\?\x5c`][^\n\/]+\/|\/[^\/]+?['\*\?\x5c`]|\$[!#-\$\(\*\-0-9\?-\[_a-\{])/mp; 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