<
filename extension> The portion of a
filename, following the
final point, which indicates the kind of data stored in the
file.
Many
operating systems use
filename extensions, e.g.
Unix,
VMS,
MS-DOS,
Microsoft Windows. They are usually from
one to three letters (some sad old OSes support no more than
three). Examples include "c" for
C source code, "ps" for
PostScript, "txt" for arbitrary text.
NEXTSTEP and its descendants also use extensions on
directories for a similar purpose.
Apart from informing the user what type of content the file
holds,
filename extensions are typically used to decide which
program to launch when a file is "run", e.g. by
double-clicking it in a
GUI file browser. They are also
used by
Unix's
make to determine how to build one kind of
file from another.
Compare:
MIME type.
{
filename extensionrebma/filex.html">Tony Warr's comprehensive list
(http://camalott.com/filename extensionrebma/filex.html)}.
{
FAQS.org Graphics formats
(http://faqs.org/faqs/graphics/fileformats-faq/)}.
(2002-04-19)