Glob

Glob is a pattern-matching syntax used for filename expansion in many Unix-like systems and programming languages. The term is short for global pattern matching, describing a lightweight way to select files or paths without regular expressions. Globbing originated in early shells as a simple mechanism for pathname expansion.

Core patterns and semantics

Common glob characters include:

- *, which matches any string of characters within a single path component

- ? , which matches exactly one character

- [sequence], which matches any one character in the listed set

- [!sequence], which negates the set

Character ranges like [a-z] are supported in many implementations. Glob patterns typically operate on path components, so a pattern like a*b.txt matches files in a single directory and may not traverse subdirectories unless the implementation provides recursive matching features. Dotfiles (names beginning with a dot) are often excluded from matches unless the pattern explicitly begins with a dot or a shell option enables dotglob.

Variants and scope

Different environments extend basic globs. Bash, for example, supports the globstar option (**) for recursive matching and other extended patterns. Some languages provide slight syntax differences or additional features, but the core idea remains simple wildcard matching rather than full regular expressions. Globs are generally faster and simpler for file discovery but less expressive than regex.

Implementations

Globbing is implemented in shells (e.g., Bash, Zsh), as well as in standard libraries and language runtimes. Examples include Python’s glob module, Java’s NIO PathMatcher with glob syntax, and C’s glob(3) API. In contrast to regex, globs focus on filesystem path components and are designed for practical filename selection rather than complex text processing.

Examples

- *.txt matches all text files in the current directory

- data/*.csv matches CSV files within the data directory

- **/*.py (when supported) matches Python files across subdirectories