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

@"
"
gmi

Test String

Code Generator

Language

Generated Code

using System; using System.Text.RegularExpressions; public class Example { public static void Main() { string pattern = @"(?<timestamp_utc>\d\d\d\d\-\d\d\-\d\d\s\d\d\:\d\d\:\d\d)\s[^\s]+\sPOST\s\/RDWeb\/Pages\/[^\/]+\/login\.aspx\s[^\s]+\s[0-9]+\s-\s(?<ipaddress>[^\s]+).*\s200\s[^\n]+\n"; string input = @"2023-03-20 05:43:20 1.2.3.4 POST /RDWeb/Pages/en-US/login.aspx - 443 - 2.3.4.5 Mozilla/5.0+(Macintosh;+Intel+Mac+OS+X+10_15_7)+AppleWebKit/537.36+(KHTML,+like+Gecko)+Chrome/109.0.0.0+Safari/537.36 https://your.rdsserver.org.uk/RDWeb/webclient/ 200 0 0 15 2023-03-20 15:33:46 1.2.3.4 POST /RDWeb/Pages/en-US/login.aspx ReturnUrl=%2FRDWeb%2FPages%2Fen-US%2FDefault.aspx 443 - 2.3.4.5 Mozilla/5.0+(Windows+NT+10.0;+Win64;+x64)+AppleWebKit/537.36+(KHTML,+like+Gecko)+Chrome/111.0.0.0+Safari/537.36 https://your.rdsserver.org.uk/RDWeb/Pages/en-US/login.aspx?ReturnUrl=/RDWeb/Pages/en-US/Default.aspx 200 0 0 2265 2024-03-15 00:04:49 1.2.3.4 POST /RDWeb/Pages/en-US/login.aspx - 443 - 36.133.118.254 node-fetch/1.0+(+https://github.com/bitinn/node-fetch) - 200 0 0 763 2024-03-21 02:47:46 1.2.3.4 POST /RDWeb/Pages/en-US/login.aspx - 443 - 41.185.8.146 - - 200 0 0 391 "; RegexOptions options = RegexOptions.Multiline | RegexOptions.IgnoreCase; foreach (Match m in Regex.Matches(input, pattern, options)) { Console.WriteLine("'{0}' found at index {1}.", m.Value, m.Index); } } }

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 C#, please visit: https://msdn.microsoft.com/en-us/library/system.text.regularexpressions.regex(v=vs.110).aspx