Regular Expressions 101

@regex101
Donate
Sponsor
Contact
Bug Reports & Feedback
Wiki
Whats new?

Save & Share

  • Save Regex
    ctrl+s
  • Update Regex
    ctrl+⇧+s

Flavor

  • PCRE2 (PHP >=7.3)
  • PCRE (PHP <7.3)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java 8

Function

  • Match
  • Substitution
  • List
  • Unit Tests

Tools

Sponsor
Jamstack at Scale
/
(?<!\d|^)(?<!(?<![^\W_])(?:sha|md))(?=\d)|(?<=\d)(?!\d|$)|_
/
gm
All the errors detected are listed below, from left to right, as they appear in the pattern.
? The preceding token is not quantifiable
? The preceding token is not quantifiable
? The preceding token is not quantifiable
? The preceding token is not quantifiable
Your regular expression does not match the subject string.

Regular Expression
No Match

/
/
gm

Test String

Substitution

Processing...

Code Generator

Language

Generated Code

Loading code sample...
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

Regular Expressions 101

Please wait while the app is loading...