Regex Metacharacters and Flags Cheat Sheet
This quick reference guide covers all commonly used regex metacharacters, quantifiers, and flags.
1. Metacharacters and Shorthand Classes
| Symbol | Matches |
. | Any character except newline |
\d | Any digit (0-9) |
\D | Any non-digit |
\w | Any word character (a-z, A-Z, 0-9, _) |
\W | Any non-word character |
\s | Any whitespace character |
\S | Any non-whitespace character |
2. Quantifiers
| Symbol | Meaning |
* | Zero or more |
+ | One or more |
? | Zero or one (optional) |
{n} | Exactly n times |
{n,m} | Between n and m times |
*? / +? | Lazy (non-greedy) version |
3. Anchors and Assertions
| Symbol | Meaning |
^ | Start of string or line |
$ | End of string or line |
\b | Word boundary |
(?=...) | Positive lookahead |
(?!...) | Negative lookahead |
(?<=...) | Positive lookbehind |
(?<!...) | Negative lookbehind |
4. Flags (JavaScript)
| Flag | Purpose |
g | Global — find all matches, not just the first |
i | Case-insensitive matching |
m | Multiline — ^ and $ match start/end of each line |
s | Dot-all — . also matches newlines |
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