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

Code Generator

Language

Generated Code

const regex = /(?<=version:\s\s\s\s\s\s\s\s)\d+(\.\d+)+/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('(?<=version:\\s\\s\\s\\s\\s\\s\\s\\s)\\d+(\\.\\d+)+', 'gm') const str = `filename: /usr/lib/modules/5.7.7-967.native/kernel/drivers/video/nvidia.ko alias: char-major-195-* version: 450.57 supported: external license: NVIDIA srcversion: CCB2AEF641D4CD7A82E48B3 alias: pci:v000010DEd*sv*sd*bc03sc02i00* alias: pci:v000010DEd*sv*sd*bc03sc00i00* depends: retpoline: Y name: nvidia vermagic: 5.7.7-967.native SMP mod_unload parm: NvSwitchRegDwords:NvSwitch regkey (charp) parm: NvSwitchBlacklist:NvSwitchBlacklist=uuid[,uuid...] (charp) parm: nv_cap_enable_devfs:nv_cap_enable_devfs=0 or 1 (int) parm: NVreg_ResmanDebugLevel:int parm: NVreg_RmLogonRC:int parm: NVreg_ModifyDeviceFiles:int parm: NVreg_DeviceFileUID:int parm: NVreg_DeviceFileGID:int parm: NVreg_DeviceFileMode:int parm: NVreg_InitializeSystemMemoryAllocations:int parm: NVreg_UsePageAttributeTable:int parm: NVreg_MapRegistersEarly:int parm: NVreg_RegisterForACPIEvents:int parm: NVreg_EnablePCIeGen3:int parm: NVreg_EnableMSI:int parm: NVreg_TCEBypassMode:int parm: NVreg_EnableStreamMemOPs:int parm: NVreg_EnableBacklightHandler:int parm: NVreg_RestrictProfilingToAdminUsers:int parm: NVreg_PreserveVideoMemoryAllocations:int parm: NVreg_DynamicPowerManagement:int parm: NVreg_DynamicPowerManagementVideoMemoryThreshold:int parm: NVreg_EnableUserNUMAManagement:int parm: NVreg_MemoryPoolSize:int parm: NVreg_KMallocHeapMaxSize:int parm: NVreg_VMallocHeapMaxSize:int parm: NVreg_IgnoreMMIOCheck:int parm: NVreg_NvLinkDisable:int parm: NVreg_EnablePCIERelaxedOrderingMode:int parm: NVreg_RegisterPCIDriver:int parm: NVreg_RegistryDwords:charp parm: NVreg_RegistryDwordsPerDevice:charp parm: NVreg_RmMsg:charp parm: NVreg_GpuBlacklist:charp parm: NVreg_TemporaryFilePath:charp parm: NVreg_AssignGpus:charp`; // 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