RegEx Tutorial — One-Page Cheat Sheet

Pattern matching that's useful — and safe.

RegEx Basics

• HOME
• Intro
• Literals & Metachars
• Character Classes
• Anchors ^ $ \b
• Quantifiers
• Groups & Capture
• Alternation
• Look-ahead / behind
• Flags (i / g / m / s / u)

Practical RegEx

• JS RegExp
• Python re
• PHP PCRE
• SQL Regex
• grep / sed / awk
• Replace & Backrefs
• Named Groups

Patterns

• Emails (and pitfalls)
• URLs
• Dates
• Numbers
• Strip HTML (don't parse it)
• Log Lines

Safety

• Catastrophic Backtracking (ReDoS)
• Unicode
• Compile Once, Reuse
• Tools (regex101, etc.)

Examples

• Examples
• Cheatsheet
• Quiz
• Exercises
• Bootcamp
• Certificate
• Summary