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

const regex = /(?<type>.{1})(?<user_access>.{3})(?<group_access>.{3})(?<other_access>.{3}) +(?<oder>[0-9]*) +(?<owner>[a-z]*) +(?<group>[a-z]*) +(?<size>\d*) +(?<month>[a-z]{3}) +(?<day>\d{1,2}) +(?<year>\d{0,4})(?<time>(?<hour>\d{2}):(?<minute>\d{2}))? +(?<filename>(?<basename>.+)\.(?<extension>.*)|(?<no_extension_filename>.*))/gmi; // Alternative syntax using RegExp constructor // const regex = new RegExp('(?<type>.{1})(?<user_access>.{3})(?<group_access>.{3})(?<other_access>.{3}) +(?<oder>[0-9]*) +(?<owner>[a-z]*) +(?<group>[a-z]*) +(?<size>\\d*) +(?<month>[a-z]{3}) +(?<day>\\d{1,2}) +(?<year>\\d{0,4})(?<time>(?<hour>\\d{2}):(?<minute>\\d{2}))? +(?<filename>(?<basename>.+)\\.(?<extension>.*)|(?<no_extension_filename>.*))', 'gmi') const str = `total 80 drwxr-xr-x 2 root root 4096 Sep 23 15:20 bin drwxr-xr-x 3 root root 4096 Sep 3 18:41 boot drwxr-xr-x 3 root root 4096 Aug 19 20:48 build drwxr-xr-x 14 root root 3900 Sep 23 15:20 dev drwxr-xr-x 98 root root 4096 Sep 23 15:20 etc drwxr-xr-x 4 root root 4096 Oct 6 2014 home drwxr-xr-x 21 root root 4096 Aug 21 19:49 lib drwxr-xr-x 2 root root 4096 Jul 8 13:21 lib64 drwx------ 2 root root 16384 Aug 26 2014 lost+found drwxr-xr-x 2 root root 4096 Aug 26 2014 media drwxr-xr-x 2 root root 4096 Apr 10 2014 mnt drwxr-xr-x 2 root root 4096 Aug 26 2014 opt dr-xr-xr-x 133 root root 0 Sep 23 15:20 proc drwx------ 4 root root 4096 Sep 23 15:27 root drwxr-xr-x 22 root root 760 Sep 23 17:40 run drwxr-xr-x 2 root root 12288 Sep 23 15:20 sbin drwxr-xr-x 2 root root 4096 Aug 26 2014 srv dr-xr-xr-x 13 root root 0 Sep 23 15:20 sys drwxrwxrwt 2 root root 4096 Sep 23 17:40 tmp drwxr-xr-x 10 root root 4096 Aug 26 2014 usr drwxr-xr-x 14 root root 4096 Aug 21 19:52 var `; // 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