👉 Overview
👀 What ?
Linux Wildcards are symbols that enable users to select filenames based on patterns of characters. The wildcard characters in Linux are * (asterisk), ? (question mark), and [ ] (brackets). The * wildcard represents any number of characters, including none, while the ? wildcard represents only one character. Brackets are used to specify a range of characters.
🧐 Why ?
Understanding and using Linux wildcards is important because they provide a powerful tool for managing files efficiently. They can simplify tasks by reducing the need to enter long filenames, help in file searching, and allow for quick and efficient file management. The use of wildcards can significantly improve the productivity and efficiency of working with Linux systems.
⛏️ How ?
Using Linux wildcards is quite straightforward. For instance, to list all files that end with .txt, you would use the command 'ls *.txt'. To list all files that start with a and end with .txt, use 'ls a*.txt'. To list all files that have exactly two characters in their names, use 'ls ??'. To list all files that start with a or b, use 'ls [ab]*'.
⏳ When ?
The use of wildcards in Linux started since the early development of Unix-like operating systems, where they were incorporated into the design of the shell to provide users with flexible file management capabilities.
⚙️ Technical Explanations
In Linux, wildcards are interpreted by the shell before any command is executed. This process is known as 'globbing'. For example, when a user enters a command like 'ls *.txt', the shell first expands the wildcard pattern (*.txt) to match any filenames that end with .txt. The ls command is then executed with these filenames as arguments. This process is done by the shell, not the command itself. It's also important to note that, by default, if a wildcard pattern doesn't match any filenames, the command is executed with the literal wildcard pattern as an argument.