Wildcard

Wildcards are simplified pattern-matching characters: * matches any sequence and ? matches a single character; commonly used for file-name and domain matching.

Purpose

Provides the simplest pattern-matching mechanism, suited to non-technical users and simple matching scenarios.

Mechanism

* matches zero or more arbitrary characters; ? matches exactly one arbitrary character. Some implementations support the [] character class. No grouping, no quantifiers, no escaping (or limited escaping). In DNS and certificate SANs, *.example.com matches subdomains.

Use cases

DNS wildcard resolution
SSL certificate wildcard domains
Shell file-name expansion
Simple matching in search boxes

Examples

Input

*.example.com

Output

Matches a.example.com, b.example.com

Wildcard domain

Common errors

Wildcard certificates matching multi-level subdomains (a.b.example.com does not match): Wildcards match a single level only; multi-level subdomains need separate certificates

Related terms

Glob

Glob is shell-style file-path pattern matching that uses wildcards such as * ** ? [] to match file names; it is simpler than regex.

GLOSSARY

Regular Expression

A regular expression is a formal language for describing string patterns, defining matching rules with metacharacters and quantifiers; it is widely used for search, validation, and extraction.