List of unused file extensions?

[crazyfuturamanoob]

I find many lists of file extensions in use with google.

But no any list of file extensions not used anywhere. Do you know if there are any?

That list won't be long for sure.

[Eisenwinter]

I doubt you'd find a list of unused file extensions.

Why would they come up, and if they're unused?

[jimi_hendrix]

its ok to re-use file-extensions...if you look at some of them you will notice they mean two or three different things

[LowSky]

its ok to re-use file-extensions...if you look at some of them you will notice they mean two or three different things

Give me one example of a re-used file extension.

[conundrumx]

Give me one example of a re-used file extension.

.dat

[MaxIBoy]

Dunno if .dat counts, because it just means "data," it's a catch-all file format.


I suggest using a standard file format like .xml or .gz.

Most recently-made file formats are renamed archives or text files, anyway. Like the .pk3 files you find in Quake III? Those are renamed .zip files. Or the .odt files openoffice uses? Also renamed .zip files. And .deb packages? Those are renamed .ar files (not to be confused with the .tar format.) It's just a more-efficient way of doing things.

And these days, it simply makes sense not to rename the file extension, so people know how to edit them.

Raymond's The Art of Unix Programming has A chapter with information about file formats (http://www.catb.org/~esr/writings/taoup/html/textualitychapter.html).





As far as answering your actual question goes, though, I'd start by making your file extension and looking to see if it already exists.

[HermanAB]

Linux doesn't need file extensions. Any self respecting program uses a utility called 'file' to identify file types.

That is why you can store a JPEG file with a .txt extension and the Gimp will still be happy with it.

Cheers,

Herman

[Thelasko]

Give me one example of a re-used file extension.

.ldf (http://filext.com/file-extension/LDF) (sorry for the crappy site)

That's just one of many, many more.

[wmcbrine]

Assuming we're talking three letters here (and ignoring the many extensions that incorporate digits), that's 26^3 possible values, or 17576. Not surprising that there wouldn't be a list of unused extensions, especially since there's no registrar or controlling authority.

[jimi_hendrix]

Assuming we're talking three letters here

it can be more now can it not?

[spupy]

it can be more now can it not?

Oh U! My DOS-based operating system support only 3 characters for extensions. :)

I don't know, aren't 3 character extension still popular, despite having no reason for this limitation?

[wmcbrine]

Yep, the only reason three-letter extensions hang around now is tradition, established in the FAT era, when it was a fixed limit.

Of course if you allow more characters, the search space just gets bigger, making the idea of a list of unused extensions even less likely.


Give me one example of a re-used file extension..doc

Yeah, nowadays you look at that and think "that's a Microsoft Word file". But it wasn't always so. I used to use it for plain text documentation files, following a then-common practice.

[Skripka]

it can be more now can it not?

Quick, what linux app has a "*.xspf" extension for certain files? ;)

[kavon89]

Here is a website (http://filext.com/) which has a large library of file extensions and programs which use the same extension to distinguish their format.

There isn't like a registry or anything for file extensions which says which ones are available... just make one up if your program writes files in a non-standard way.

[spupy]

Funny, I've never met file extensions like "iii", "rrr" or "hhh". :)