Should "B" be the Same as "b"?

joshua42 asks: "Although having used Linux and FreeBSD for many years, I have yet to come across anyone seriously questioning the traditional UNIX style file system name paradigm. With an Amiga background (It should be the same for people growing up with Windows, or those growing up with no computer at all (God forbid!).) it took me quite a while to get used to 'A' and 'a' being treated as different characters. This is of course fairly easy to accept and to understand if you have a technical background. I do however have a hard time to see how aunt Ginny will ever be able to distinguish between her 'Letter.txt', 'LETTER.TXT' and 'letter.txt' files. In real life, upper and lower case letters represents almost identical information to most people. Has any thoughts been spent on this issue, now that our favorite OS is becoming increasingly mainstream? Does it need to be addressed? Have any attempts been done? What are the implications to parts outside the file systems?" This is an interesting point. As Unix grows more and more popular, the simple things we've taken for granted about the filesystem may stand in the way of general users adopting it. What ways can you think of that will mitigate this problem for new Linux users without actually affecting too much? Special shells for novice users, that can simplify much of the complexity may be the way to go, here.

Comments

Apple....

[jeffy124]

Apple OSX is already case-insensitive in terms of filenames, probably for the reason mentioned. MS Windows/DOS have probably all done that for the exact same reason as well.

Of course, in OSX this did cause a security hole in Apache, but it was small, required a specific setup, and was easily fixed.

Re:Apple....

[medcalf]

Actually, OS X per se is not this way. The HFS+ filesystem used by OS X is this way. Using UFS on OS X (built-in and easily used if you want to) uses a case-sensitive, rather than simply case-preserving, filesystem.)

Re:Sort order

[Papineau]

That behavior depends on your locale.

Let's say I have a file with the following (meaningless) unsorted content:
asklhf
Adjgd
zaskd
Zaoifh

If I sort it with LC_ALL=posix sort myfile, here's what I get:
Adjgd
Zaoifh
asklhf
zaskd

Now, that is exactly the kind of behavior that you dislike.
Try this (LC_ALL=en_US sort myfile) now:
Adjgd
asklhf
Zaoifh
zaskd

Much like you wanted it to be, right? The C locale seems to give the same results as posix, and fr_CA gives the same thing as en_US. I'll leave it to somebody else to explain it by looking in a specific standard, or in the source code.

So in short, check that your locale is correctly specified, and sort should do what you want it to do. Or, you could just use the --ignore-case of sort.

Or were you talking about something system-wide, for ls, file selection boxes, etc.? Then it depends on where the sorting is done, and might be more difficult to fix (since you'll always miss one place).

In the meantime...

[dar]

For bash users: Add the following to the .inputrc in your home dir.

set completion-ignore-case on

Then when hitting tab to complete a filename, it will fix the case for you. i.e. typing "vi xf8" and pressing tab will get you "vi XF86Config" etc.

Re:Preserve Case but don't make it case sensitive

[sigwinch]

The only reason why Unix is case sensitive is because it was easier, and faster to implement it as such in the early days.

No, it's because case sensitivity is the Right Thing.

It is also a security concern. If I have 2 files, which are identical except for case it is possible I could run the wrong one. Why? Point and Click interfaces barely show a difference between o and O, etc.

If by "Point and Click" you mean "the egregiously bad fonts chosen for Windows", I agree. They have other problems, such as "1Il" (one capital-eye lowercase-ell) and "O0" (oh zero). (Will the real Bruce Perens please stand up? ;-)

There is also no need for 2 files with the same name, and different case when it comes to SOURCE CODE. I have seen more than 1 program implemented like this and it is downright confusing and stupid. " No no, not "ubergeek.c", "Ubergeek.c"... etc.

On the other hand, it is arguably useful to distinguish between file.c and file.C.

I've been working in a database language that is case-insensitive for a number of years as well. It is damn nice to not have to worry about somebody typing something in differently than expected. It isn't a problem. And I don't have to call UPPER every time I do something!

All computers are not Vaxes. All text is not 7-bit ASCII. For a general purpose Unicode-compatible system, **THERE IS NO WAY TO BE CASE INSENSITIVE**. Period. End of story. No further discussion. How do you handle "Â" versus "â"? Or "" versus ""? (Capital thorn versus small thorn.) Or "Æ" versus "aE"? Or similar things for terrorist languages like Arabic and Klingon? Or the Russian letter whose name escapes me that looks exactly like a capital "O" but *isn't*. (That one's good for all sorts of fun.) The answer is that you don't even try. Anything you do is going to break badly, and a system that is randomly broken is less useful than a system that is consistent.

Re:Flame-baitey topic

[Paul Jakma]

yes there is a good reason. and it is not about "removing" case-sensitivity, it's about adding it.

The basic issue is that Unix filesystems at the kernel level do not interpret filesystems in /any/ way what so ever. The only restrictions on Unix filesystem names is that no byte within a name may equal '\0' or '/'. You can put whatever characters or bits you want in a filename as long no byte equals ASCII \0 or /.

This means no "tolower()" or case comparison overhead in the kernel. No complicated (and perhaps non-obvious) policy in the kernel.

It also means filename schemes are easily extensible in userspace. Eg, Unix filesystems support Unicode, UTF-8, ISO8559-[0-9][0-9], and whatever other encoding system you want provided you respect '\0' and '/'. In fact Unix supported Unicode, UTF-8, etc.. almost from day one (ie 1970), literally /before/ these 'beyond ASCII' schemes were even invented. Unix filesystems also support many many other future encoding schemes that have not been invented yet. :)

Basically, tolower() / case comparison can be easily done in userspace - hence that is the best place for it. Now, of course, userspace might not always agree on policy or how to implement it, but that is not a kernel problem.

Case sensitivity is a matter of taste, and as such it's best not done in the kernel (where it will be set in stone forever). That's actually a general Unix design principle "policy should be implemented in userspace" - and it's actually a very good design principle..

now let's see how many slashdotters fail to realise it..