Extensions, for all you Mac users, is the three to four letter attachment to the end of a file name which flags it underneath the header of a specific program or application type. It tells the computer what encoding is in the file so that the computer knows what to do with it. Coming in from the old days of DOS, a file named [REYPOST space TXT] would be opened by a text (txt) editor. This got confusing so over time the OS switched to using reypost.txt. Apple, for all its slickness, has the uber stupidity of still allowing files to be named without extensions.

“But we don’t need filename extensions.” say the mindless Apple drones. Okay, that’s sort of true since Apple is built on a Unix-like OS which allows the computer to assign permission to files instead of putting the .exe extension at the end of every program but its also very untrue because the “unix-like OS which Apple uses didn’t thave type or creator code support in its file system.”

So Macs use (1) Filenames, (2) multipurpose Internet mail extensions and (3) file type codes to tell the Mac what a file is. And yet, some programs give you the option to save without the extension–which is just plain dumb. You see, when an extensionless file gets sent OUTSIDE of the mac, all that yummy Internal Mac information disappears. Even if its from Mac to Mac or from Mac to FTP to Mac!

I don’t know how many times I’ve gotten an emailed quark, photoshop eps, illustrator eps, tiff, jpg file without an extension on the tail end and have to either (A) sit and wait for my friend/client to tell me or (B) try every extension on copies of the file until it opens in the right program.

So do me a favor folks: make sure you use your extensions. There’s no good reason not to. (Mind you, this article deals with OS 10.4. If 10.5 Leopard forces programs to add filename extensions rendering my rant moot, then so be it. But I doubt we all went out and bought Leopard.)