Windows file type and open Mode definition method _dos/bat

Assoc: Defines the file type based on the file name extension. You can use this command to display or modify file name extension associations
For example:
. bat=batfile
. xls=excel.sheet.8

Ftype: The Open method is defined according to the file type. You can use this command to display or modify file types that are used in association with file name extensions
For example:
batfile= '%1 '%*
excel.sheet.8= "C:\Program Files\Microsoft Office\office\excel. EXE "/e

Description
The basic use format for Ftype is: Ftype [File Type [=[open mode/program]
For example, the ftype exefile=notepad.exe% 1 In the example above indicates that all files of the file type EXE (exefile as an EXE type file) are opened through the Notepad program, and the following%1 represents the program itself (the one that was double-clicked).
Ftype exefile=%1%* means that all EXE files are run directly (EXE can be run directly, so use%1 to represent the program itself), followed by%* to represent all the parameters after the program command (which is why EXE files can run with parameters).

So, if there is a problem with the System file type and association, we can just reset it with these two commands.