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Comment by Alupis | Hacker News Reader

I've only ever seen Windows-based systems adhere strictly to the 3-character extension. All 'Nix's I've worked with (Linux, BSD's, etc) usually have native files on the system with extensions longer than 3 characters. (.conf anyone?)

Also, probably should note, file extensions are largely a Windows-based OS thing as well. On the 'Nix's, an extension isn't really needed (OK, it's not needed on Windows-based OS's either, but the OS prefers it). the "file" command will tell you all you need to know about a file without an extension. Or, you can just open it with a text editor. Or, execute it if it has execute permissions, etc.

So, it seems, the 3-character extension (or extensions at all) are really a Windows-Based OS thing.

(While we're at it, Windows-Based OS's are the only OS's I've worked with that actually require something in-front of the "."! For example, try to natively create a ".somefile" on Windows -- it will complain and not let you).

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Windows has allowed extensions longer than 3 characters for about 20 years now. I'm not sure what you mean by "natively create" but it also definitely doesn't require anything before the "." -- e.g. I have files called ".gitignore" etc. just as on any other OS.

Right click a text file (such as "example.txt") and try to rename to ".gitignore". You get an error popup dialog "Rename: You must type a file name."

That's what he means...you can create it in various applications though.

That is the most annoying error ever. No, I must not! I shall decide for myself what I must and mustn't do! /me opens cmd.exe and uses ren untitled.txt .gitignore

A slightly bigger challenge is a file named CON :)

Or .... , but that one is fairly easy as long as you COPY from the CONsole to a <fileName>. And remember ^Z to save and quit.

Yes, UNIX's never had a concept of a limited length file extension. Until the 1980s filenames were limited to 14 characters in total, but you could put a dot anywhere you like in it.

I was specifically referring to the part of the article that the author claimed that windows inherited it from MS-DOS, which inherited it from CP/M. The chain goes back farther than that -- by the time CP/M was written the 3-character file extension was well-established. In general CP/M was influenced a lot by the DEC minicomputer OSes (its "PIP" command is one obvious example)

> UNIX's never had a concept of a limited length file extension

AFAICT, UNIX never had a concept of file extensions.

At the filesystem layer? No, never. However even in the earliest of days file extensions were common. They followed the usual UNIX preference for brevity: ".c", ".h", ".o", and ".a" were all early arrivals. So even though they didn't cram extensions into the filesystem, they weren't allergic to it as a convention.

In the 80s you started seeing things like "resolv.conf" appear, so they didn't stay mostly-single-character for long.

In Windows Explorer it will complain if you try and create a file starting with a dot, but I suspect that it's because extensions are hidden by default, so you'd end up creating a file with no name.

Can easily create such files by other means (saving in notepad, sublime, etc).

There's a trick. You can for example name a file .gitignore. (with a starting and trailing dot), it will warn you about changing the extension which you agree to, and you're left with a file named .gitignore

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