Windows commands for setting default applications for opening certain file types

On Friday, I was working on a system where a session is instantiated from a stored virtual machine that produces a fresh session every time so all previous changes get lost. What I have is a batch script that I run to reinstate what I need and I encountered another task that I wanted it to do.

Part of my work involves the creation of plain text files with the extension lst and this is getting associated with SAS instead of Notepad. While you can reassign such associations using the GUI, it would be nice to do it via the command line too so the assoc and ftype commands caught my interest. The first of these associates a file with a given extension with a desired file type while the second shows the available file types together with the associated applications that open them. The assoc command also show all the associations that are in place when it is executed with no parameters and the ftype command does the same for file types.

Once you have picked out a file type with the ftype command, then the assoc can be used like the following:

assoc .lst=txtfile

The above associates an extension with a file type. In the this, .lst files are going to get opened by Notepad because of the txtfile association. Though it did not do what I wanted on Friday due to system lockdown, it is good to know that this is possible and that even the Windows command line supports goodies like these.