Change Default Application

Alright, I’ve had enough. When­ever I open an .tor­rent file, Opera auto­mat­i­cally opens, and not Trans­mis­sion. So how do I change a file’s default application?

First, find that file (in my case, a .tor­rent file) and right click (or con­trol + click) it. Select “Get Info” from the menu.

From this menu, click the tri­ange beside the “Open With” pane to reveal the default appli­ca­tion switcher.
Select your app from the drop down menu (I want Trans­mis­sion) and then click “Change All“
Voila! Close the win­dow!
Note: Oh, and if you only want that sin­gle file to open in that pro­gram, and all the rest to still stay in the other type, don’t click “Change All”. Just close the window.