Posted by Toby A Inkster on 12/19/07 15:42

Captain Paralytic wrote:

> How do you define a valid filename?

Good question. As far as I know, for Linux and most UNIXy OSes it's this:

#[^/]#

i.e. any string that doesn't contain a slash is a valid filename. (Because
of course, the slash must be a directory separator.) Any other character
is valid in a file name -- asterisks, question marks, colons, tabs, line
feeds, whatever. Names "." and ".." are technically allowed, but they
always already exist.

It does depend on the filesystem though. Linux supports dozens of
different filesystems and some of those will limit you further.

Windows is a more fussy. As well as slashes, it doesn't allow colons,
backslashes, asterisks, question marks, whitespace other than the space
character itself, less-than and greater-than signs, double quotes and the
pipe symbol. There are also a small number of reserved file names that
cannot be created, such as "CON", "PRN", "CLOCK$" and "LPT1" -- these
special filenames were used to represent various hardware devices in DOS.

--
Toby A Inkster BSc (Hons) ARCS
[Geek of HTML/SQL/Perl/PHP/Python/Apache/Linux]
[OS: Linux 2.6.17.14-mm-desktop-9mdvsmp, up 12 days, 2:00.]

Sharing Music with Apple iTunes
http://tobyinkster.co.uk/blog/2007/11/28/itunes-sharing/

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