Most Mac applications are neatly packaged, but you can easily peek inside using Finder or Terminal. App package contents typically include executable files, resources, configurations, and ...

If you use these commands to change your Mac's behavior and want to undo it, you can open up Terminal and enter sudo nvram -d BootPreference.

If you're comfortable pasting commands into Terminal, it's perfectly possible to increase or decrease the number of recently opened apps that show in your Dock.