Tại sao có dir *. * Liệt kê tất cả các tệp và thư mục?

When I run the dir *.* command, it produces unexpected results. Even files and folders without any dot in the name are listed. For example:

The DIR command comes from a time when:

• A period (.) was not allowed as a character in file or folder names
• File and folder names were restricted to 8 characters for names and 3 characters for extensions

Therefore, by that standard, *.* meant whatever the name and whatever the extension. It did not mean a string containing a “.”, which may or may not have characters before or after the “.”.

Microsoft’s policy is preserving backward compatibility, so that interpretation of *.* is retained. But in Windows PowerShell, *.* means a string containing a “.”, which may or may not have characters before or after the “.”.