What is *?

*. is a common wildcard character used in computing and especially in filename extensions.

Purpose: It serves as a placeholder, representing "any" or "all" when used with file names or commands.

Usage Examples:

• *.txt: Selects all files ending with the .txt extension (i.e., all text files).
• *.: Selects all files regardless of their extension, or even those without extensions in some contexts. This is not a very common or useful use case.
• program.*: Selects all files that start with "program" regardless of their extension.

Common Applications:

• File Selection: Used in command-line interfaces (like CMD in Windows or Bash in Linux/macOS) and file management tools to select multiple files at once.
• Batch Processing: Used in scripts or batch files to perform operations (e.g., copying, deleting, renaming) on a group of files.
• Search: Used in search tools to find files that match a certain naming pattern.
• Programming: Sometimes used in programming languages (though less common than explicit loops) for file system operations.

Important Note: The behavior of *. can vary slightly depending on the operating system and the specific command or tool being used. It's generally best practice to test how it behaves in your particular environment to avoid unexpected results. For example, whether it matches files without extensions might depend on the operating system.