filename: The name of a file. A filename must be unique within the directory that contains it (I guess this is true even for the Vax filesystems that automatically save old versions with a numbered (automatically incremented) extension).

A filename can include a path (which specifies the directory that the file is in, the simple filename (the name within a directory (without the extension??)), and a filename extension usually using the "." as a delimiter.

When you simply say filename, you could mean any of these. To specify the complete filename (with path and extension) you might say "fully qualified filename" (or maybe "full pathname"?).

Different operating systems have different restrictions on the length and contents of a filename. (MS)dos had the 8.3 limitation on a filename, allowed only one period, and disallowed characters like \/ (and others). I think the limitation in Linux is 256 characters, but I'm not sure whether that's a limitation on the simple filename or on the overall "fully qualified filename". A Linux filename can include more than one extension.

Contributors

• RandyKramer - 31 Jan 2002
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