Bash 101: Introduction to File Globbing

Bash globbing is a fundamental feature that allows you to match multiple filenames or paths using wildcard characters. This feature is essential when working with files in a Linux environment, as it helps automate and manage tasks efficiently. In this guide, we'll dive into the details of globbing, covering its syntax, usage, and some practical examples to help you master this powerful concept.

What is Bash Globbing?

Globbing in Bash is the process of using wildcard characters to match filenames or paths. Unlike regular expressions, which are used in commands like sed or awk, globbing is specifically for filename expansion within the shell. The most commonly used wildcards in globbing are:

• `` (Asterisk): Matches zero or more characters in a filename or path.

• ? (Question Mark): Matches exactly one character.

• [] (Square Brackets): Defines a character class to match any single character within the brackets.

These characters allow you to work with groups of files or directories without specifying each one individually.

Matching Any String with `*`

The asterisk * is perhaps the most versatile wildcard in globbing. It can match any string of characters, including an empty string, which makes it incredibly useful for listing or manipulating files.

For example, to list all files in the current directory, you can use:

$ ls *

To narrow it down to files with a specific extension, like .txt files, you would use:

$ ls *.txt

This command will list all files ending with .txt in the current directory, regardless of what comes before the extension.

Matching a Single Character with ?

The question mark ? is used to match exactly one character in a filename. This is useful when you know the structure of a filename but need to match files with slight variations.