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

/
/
iJxmg

Test String

Code Generator

Generated Code

use strict; my $str = ';An orphan comment at the top of the file #Another orphan comment #Comment above a group [Group1] #Group comment 1 Key1=Value1#Comment 1 Key2=Value 2 Key 3=Value 3 Key 4=Value4 Key5=Value \\#5;Comment 2 ;Another comment above a group [Group 2] ;Group comment 2 Key1 = Value1 #Comment 3 Key2 = Value 2 Key 3 = Value 3 Key 4 = Value4 Key 5 = Value\\;5 ;Comment 4 Key 6 = Value\\;6\\#1 ;Comment 5 Key 7 ;Comment 6 Key 8 = Value;7 \\\\;Comment 7 Key 8 =;Comment 7 Key 9 = Value\\\\;8 ;Comment 8 ; with quotes ;An orphan comment at the top of the file #Another orphan comment #Comment above a group [Group1] #Group comment 1 Key1="Value1"#Comment 1 Key2="Value 2" Key 3="Value 3" Key 4="Value4" Key5="Value \\#5";Comment 2 ;Another comment above a group [Group 2] ;Group comment 2 Key1 = "Value1" #Comment 3 Key2 = "Value 2" Key 3 =" Value 3" Key 4 = "Value4" Key 5 = "Value\\;5 ;Comment 4" Key 6 = "Value\\;6\\#1 ";Comment 5 Key 7 ;Comment 6 Key 8 = "Value;7 \\";Comment 7 Key 8 ="";Comment 7 Key 9 = "Value\\\\";8 ;Comment 8 '; my $regex = qr/^[^\S\r\n]* (?: \s* (?<section>\[[^\]]*\]) [^\S\r\n]* (?<comment>(?:[#;].*)?) | (?<comment>(?:[#;].*)?) | (?: (?<key>[^#;]+?) \s* = [^\S\r\n]* (?: (?: "(?<value_quote>.*)" | (?<value>(?:[^#;\r\n\\\s]*[\s]??(?:\\.)*)*) ) [^\S\r\n]* (?<comment>(?:[#;].*)?) ) ) | (?<error>.*) ) $/ixmp; 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