MS-DOS and Windows command line assoc command
The assoc command displays the file association for each of the different file extensions on the computer.
The assoc command is an internal command that is available in the following Microsoft operating systems.
Displays or modifies file extension associations.
|.ext||Specifies the file extension to associate with the file type.|
|fileType||Specifies the file type to associate with the file extension.|
Type ASSOC without parameters to display the current file associations.
If ASSOC is invoked with only a file extension, it displays the current file association for that file extension. If you specify nothing for the file type, the command deletes the association for the file extension.
Displays a file association of each of the file extensions on the computer.
Displays the file extension for a .txt file as shown below.