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

Substitution

Processing...

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"(?m)^([A-Za-z]{3} {1,2}[0-9]{1,2} {1,2}([0-9]{2}:){2}[0-9]{2}).* (delay=([0-9]{2}):([0-9]{2}):([0-9]{2})).*").unwrap(); let string = "Mar 19 06:10:16 ip-172-2-0-53 sendmail[28131]: v2JDA1k4028131: to=root, ctladdr=root (0/0), delay=00:00:15, xdelay=00:00:00, mailer=relay, pri=30580, relay=[127.0.0.1] [127.0.0.1], dsn=2.0.0, stat=Sent (v2JDAG5W028134 Message accepted for delivery) Mar 19 14:41:26 ip-172-2-0-53 sendmail[29483]: v2JLfNFN029481: to=<tsturdsi@ifaded.com>,<kgogineni@ifaded.com>, delay=00:00:03, xdelay=00:00:03, mailer=esmtp, pri=151738, relay=ifaded-com.mail.p...ction.outlook.com. [xx.xxx.x.x], dsn=2.0.0, stat=Sent (<4253fc91a05d91ce3b5f5147278dfae9@heg.jkadionbub.com> [InternalId=31288836753166, Hostname=ERGDGD5.namprd07.prod.outlook.com] 8924 bytes in 0.309, 28.142 KB/sec Queued mail for delivery) Mar 19 06:10:26 ip-172-2-0-53 sendmail[28131]: v2JDA1k4028131: to=root, ctladdr=root (0/0), delay=00:20:15, xdelay=00:00:00, mailer=relay, pri=30580, relay=[127.0.0.1] [127.0.0.1], dsn=2.0.0, stat=Sent (v2JDAG5W028134 Message accepted for delivery) "; let substitution = "\\4\\5\\6 \\1 \\3"; // result will be a String with the substituted value let result = regex.replace_all(string, substitution); println!("{}", result); }

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/