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

/
/
mgi

Test String

Code Generator

Language

Generated Code

use strict; my $str = '[mysqld] skip-grant-tables # k bind-address=127.0.0.1 port = 3307 # test basedir=C:\\Program Files (x86)\\MySQL\\ datadir=C:\\Program Files (x86)\\MySQL\\data\\ default-storage-engine=INNODB sql-mode= " STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,test NO_ENGINE_SUBSTITUTION" #test max_connections=1000 tmp_table_size=1G max_heap_table_size=1G join_buffer_size=1M query_cache_size =50M query_cache_limit=50M max_allowed_packet = 104857600 port = = fh thread_cache_size=8 #*** MyISAM Specific options myisam_max_sort_file_size=100G myisam_sort_buffer_size=35M key_buffer_size=25M read_buffer_size=64K read_rnd_buffer_size=256K sort_buffer_size=256K #*** INNODB Specific options *** innodb_flush_log_at_trx_commit=0 innodb_log_buffer_size=50M innodb_buffer_pool_size=1000M innodb_log_file_size=300M innodb_thread_concurrency=8 innodb_flush_method=normal innodb_autoinc_lock_mode=0 test=0 '; my $regex = qr/^(?!\s*$)\s*(?!\s)([^#\n\[=]+?)\s*?(?>#.*?$|(?>=\s*$|=\s*?(?:#?|(".*?"|[^\s].*?)\s*?)(?:\s*#.*?$)*?$)?$)/mip; 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