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

const regex = /file type.*/g; // Alternative syntax using RegExp constructor // const regex = new RegExp('file type.*', 'g') const str = `Symbols from "/mnt/home/petros/test". Local exec file: \`/mnt/home/petros/test', file type elf64-x86-64. Entry point: 0x1050 0x0000000000000318 - 0x0000000000000334 is .interp 0x0000000000000338 - 0x0000000000000368 is .note.gnu.property 0x0000000000000368 - 0x0000000000000388 is .note.ABI-tag 0x0000000000000388 - 0x00000000000003ac is .gnu.hash 0x00000000000003b0 - 0x0000000000000458 is .dynsym 0x0000000000000458 - 0x00000000000004da is .dynstr 0x00000000000004da - 0x00000000000004e8 is .gnu.version 0x00000000000004e8 - 0x0000000000000508 is .gnu.version_r 0x0000000000000508 - 0x00000000000005c8 is .rela.dyn 0x00000000000005c8 - 0x00000000000005e0 is .rela.plt 0x0000000000001000 - 0x0000000000001017 is .init 0x0000000000001020 - 0x0000000000001040 is .plt 0x0000000000001040 - 0x0000000000001048 is .plt.got 0x0000000000001050 - 0x00000000000011d9 is .text 0x00000000000011dc - 0x00000000000011e5 is .fini 0x0000000000002000 - 0x0000000000002017 is .rodata 0x0000000000002018 - 0x0000000000002054 is .eh_frame_hdr 0x0000000000002058 - 0x0000000000002144 is .eh_frame 0x0000000000003db8 - 0x0000000000003dc0 is .init_array 0x0000000000003dc0 - 0x0000000000003dc8 is .fini_array 0x0000000000003dc8 - 0x0000000000003fb8 is .dynamic 0x0000000000003fb8 - 0x0000000000004000 is .got 0x0000000000004000 - 0x0000000000004010 is .data 0x0000000000004010 - 0x0000000000004018 is .bss `; // 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