.COM .BAT. EXE... these are a few of my favourite things. Ahhhh MS-DOS. A beautiful command line driven operating system which filled our hearts with glee. Core to this glee filled life was file formats and the programs lurking within them. These would come with either a .com .exe or .bat extension so they could be executed by a few taps on your keyboard. But what exactly is a .com file and how does it differ from an .exe or .bat file. Come to think of it, why do I care?.... I can't answer that question, but at least I can tell you how these files differ. So here we go.