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

/
/
g

Test String

Code Generator

Language

Generated Code

use strict; my $str = '2017-01-25 08:34:40 admin http://cms-site.tajawal.local:92/en/almosafer/com/block/footer/ Error: Uncaught Error: Call to undefined function ProcessWire\\getAlmosaferFooterLinks() in /var/www/cms-site/site/templates/alm-footer.php:9 Stack trace: #0 /var/www/cms-site/wire/core/TemplateFile.php(268): require() #1 [internal function]: ProcessWire\\TemplateFile->___render() #2 /var/www/cms-site/wire/core/Wire.php(374): call_user_func_array(Array, Array) #3 /var/www/cms-site/wire/core/WireHooks.php(549): ProcessWire\\Wire->_callMethod(\'___render\', Array) #4 /var/www/cms-site/wire/core/Wire.php(399): ProcessWire\\WireHooks->runHooks(Object(ProcessWire\\TemplateFile), \'render\', Array) #5 /var/www/cms-site/wire/modules/PageRender.module(514): ProcessWire\\Wire->__call(\'render\', Array) #6 [internal function]: ProcessWire\\PageRender->___renderPage(Object(ProcessWire\\HookEvent)) #7 /var/www/cms-site/wire/core/Wire.php(374): call_user_func_array(Array, Array) #8 /var/www/cms-site/wire/core/WireHooks.php(549): ProcessWire\\Wire->_callMethod(\'___renderPage\', Array) #9 /var/www/cms-site/wire/core/Wire.php(399): ProcessWire\\Wir (line 9 of /var/www/cms-site/site/templates/alm-footer.php) 2017-01-25 08:35:01 admin http://cms-site.tajawal.local:92/en/almosafer/com/block/footer/ Error: Uncaught Error: Call to undefined function ProcessWire\\getAlmosaferFooterLinks() in /var/www/cms-site/site/templates/alm-footer.php:9 Stack trace: #0 /var/www/cms-site/wire/core/TemplateFile.php(268): require() #1 [internal function]: ProcessWire\\TemplateFile->___render() #2 /var/www/cms-site/wire/core/Wire.php(374): call_user_func_array(Array, Array) #3 /var/www/cms-site/wire/core/WireHooks.php(549): ProcessWire\\Wire->_callMethod(\'___render\', Array) #4 /var/www/cms-site/wire/core/Wire.php(399): ProcessWire\\WireHooks->runHooks(Object(ProcessWire\\TemplateFile), \'render\', Array) #5 /var/www/cms-site/wire/modules/PageRender.module(514): ProcessWire\\Wire->__call(\'render\', Array) #6 [internal function]: ProcessWire\\PageRender->___renderPage(Object(ProcessWire\\HookEvent)) #7 /var/www/cms-site/wire/core/Wire.php(374): call_user_func_array(Array, Array) #8 /var/www/cms-site/wire/core/WireHooks.php(549): ProcessWire\\Wire->_callMethod(\'___renderPage\', Array) #9 /var/www/cms-site/wire/core/Wire.php(399): ProcessWire\\Wir (line 9 of /var/www/cms-site/site/templates/alm-footer.php) 2017-01-25 08:35:01 admin http://cms-site.tajawal.local:92/en/almosafer/com/block/footer/ Error: Uncaught Error: Call to undefined function ProcessWire\\getAlmosaferFooterLinks() in /var/www/cms-site/site/templates/alm-footer.php:9'; my $regex = qr/(?P<time>\d{4}-\d{2}-\d{2}\s*\d{2}:\d{2}:\d{2})\s*(?P<user>[^\s]*)\s*(?P<url>[^\s]+)\s*(?|(?P<log_msg>.*)\s*(?P<stack_trace>Stack trace:.*)|(?P<log_msg>.*))/p; 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