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

r"
"
gm

Test String

Code Generator

Language

Generated Code

const regex = new RegExp('\\d: ([\\w@]+): <(.+)> mtu (\\d+) qdisc (\\w+) qlen (\\d+)\\n[ ]+(\\w+\\/\\w+) ([\\d:\\w.]+) brd ([\\d:\\w.]+)\\n?(?:(?: )+inet6? ([\\d.:\\/]+) (?:brd ([\\d:\\w.]+) )?scope (\\w+) (?:\\w+)?\\n(?: )+valid_lft (\\w+) preferred_lft (\\w+))?', 'gm') const str = `1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue qlen 1 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: lan1: <BROADCAST,MULTICAST,UP,LOWER_UP8000> mtu 1500 qdisc mq qlen 1000 link/ether 00:60:e0:6a:48:26 brd ff:ff:ff:ff:ff:ff inet 10.32.39.55/24 brd 10.32.39.255 scope global lan1 valid_lft forever preferred_lft forever 3: lan2: <BROADCAST,MULTICAST,UP,LOWER_UP8000> mtu 1500 qdisc mq qlen 1000 link/ether 00:60:e0:6a:48:27 brd ff:ff:ff:ff:ff:ff inet 192.168.90.1/20 brd 192.168.95.255 scope global lan2 valid_lft forever preferred_lft forever 4: sit0@NONE: <NOARP> mtu 1480 qdisc noop qlen 1 link/sit 0.0.0.0 brd 0.0.0.0 6: wwp0s29u1u3i12: <BROADCAST,MULTICAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000 link/ether 00:00:11:12:13:14 brd ff:ff:ff:ff:ff:ff inet 172.16.224.124/16 brd 172.16.255.255 scope global wwp0s29u1u3i12 valid_lft forever preferred_lft forever `; // Reset `lastIndex` if this regex is defined globally // regex.lastIndex = 0; let m; while ((m = regex.exec(str)) !== null) { // This is necessary to avoid infinite loops with zero-width matches if (m.index === regex.lastIndex) { regex.lastIndex++; } // The result can be accessed through the `m`-variable. m.forEach((match, groupIndex) => { console.log(`Found match, group ${groupIndex}: ${match}`); }); }

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 JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions