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

// include the latest version of the regex crate in your Cargo.toml extern crate regex; use regex::Regex; fn main() { let regex = Regex::new(r"(?P<Timestamp>\b(?:Jan(?:uary)?|Feb(?:ruary)?|Mar(?:ch)?|Apr(?:il)?|May|Jun(?:e)?|Jul(?:y)?|Aug(?:ust)?|Sep(?:tember)?|Oct(?:ober)?|Nov(?:ember)?|Dec(?:ember)?)\s+\d+\s+\d+:\d+:\d+)\b\s+(?P<FW_ip_addr>\d+\.\d+\.\d+\.\d+)\s+(?P<Event_id>%\w+-\d+-\d+):\s+(?P<Event_message>Built (inbound|outbound) TCP connection \d+ for)\s+(?P<External_IP>.*)\s+to\s+(?P<Internal_IP>.*)").unwrap(); let string = "Jul 25 23:56:13 210.56.128.109 %PIX-6-302013: Built inbound TCP connection 71946258 for Outside:192.168.24.16/62465 (192.168.24.16/62465) to Internal:GAIA_172.20.8.11/88 (GAIA_172.20.8.11/88) Jul 25 23:56:13 210.56.128.109 %PIX-6-302013: Built inbound TCP connection 71946259 for Outside:ODC_crimson-vconf/52620 (ODC_crimson-vconf/52620) to Internal:192.168.104.121/389 (192.168.104.121/389) Jul 25 23:56:18 210.56.128.109 %PIX-6-302013: Built inbound TCP connection 71946327 for Outside:192.168.24.30/29438 (192.168.24.30/29438) to Internal:172.20.8.154/8080 (172.20.8.154/8080) Jul 25 23:56:17 210.56.128.109 %PIX-6-302013: Built outbound TCP connection 71946318 for Corp-DMZ:proxy2/8080 (proxy2/8080) to Internal:172.20.8.18/65174 (172.20.8.18/65174) Jul 25 23:56:18 210.56.128.109 %PIX-6-302013: Built inbound TCP connection 71946334 for Outside:192.168.20.21/18137 (192.168.20.21/18137) to Internal:osaka/445 (osaka/445) Jul 25 23:57:22 210.56.128.109 %PIX-6-302013: Built outbound TCP connection 71947078 for Outside:HQ_dns_server1/53 (HQ_dns_server1/53) to Corp-DMZ:210.56.134.73/48439 (210.56.134.73/48439) Jul 25 23:56:13 210.56.128.109 %PIX-6-302013: Built inbound TCP connection 71946258 for Outside:192.168.24.16/62465 (192.168.24.16/62465) to Internal:GAIA_172.20.8.11/88 (GAIA_172.20.8.11/88) "; // result will be an iterator over tuples containing the start and end indices for each match in the string let result = regex.captures_iter(string); for mat in result { println!("{:?}", mat); } }

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 Rust, please visit: https://docs.rs/regex/latest/regex/