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

/
/
gm

Test String

Code Generator

Language

Generated Code

$re = '/\"vpn_ip\":\s+\"(?<vpn_ip>\d+\.\d+\.\d+\.\d+)/m'; $str = '2023-06-21T03:29:16+0000 [stdout#info] LOG ERR: \'LOG_DB RECORD {"username": "duocnv", "common_name": "duocnv", "start_time": 1687312988, "session_id": "aa2d4wW6GaPydjA4", "service": "VPN", "proto": "UDP", "port": "1194", "active": 1, "auth": 1, "version": "3.6.7", "gui_version": "OCmacOS_3.4.2-4547", "platform": "mac", "bytes_in": 1448266, "bytes_out": 15124146, "bytes_total": 16572412, "vpn_ip": "172.27.20.2", "duration": 5168, "node": "ip-10-250-101-154.ap-southeast-1.compute.internal", "timestamp": 1687318156}\''; preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0); // Print the entire match result var_dump($matches);

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 PHP, please visit: http://php.net/manual/en/ref.pcre.php