In article , Your Name
wrote:

Your comment that they are required would only make sense if, in some
other OS you are familiar with, you can have filenames without
extensions that still open in the appropriate application by being
double-clicked on (or equivalent operation in that OS).

classic mac os did exactly that.

Yes and no.

actually, just yes.

Classic Mac OS doesn't need filename extensions as such, but does have
a similar technique stored within the file's Finder data (the File Type
and Creator codes). These just aren't visible to the general user
without using something like ResEdit, Resourcer, FileBuddy, etc.

in other words, no extensions.



The type of a file and which app you'd like it to open with are items
of file metadata and have no business being part of the filename.

It is useful and sensible to have the file type as part of the
filename.

no it's not.

Otherwise you'd get a pile of files which neither you nor the
OS having any idea whether they are images, sounds, text, etc. You
would then have to try to open the file in every app you own until you
found one that could open it ...

nonsense. it uses the type/creator to decide which app to launch when
double-clicked.

you can't rely on the OS to do that
since a JPEG image file can actually be opened in a text editor as the
file's data, even if it's rarely useful to do so.

drag the file to whatever app you want to use, and if it can handle it,
it will open it. bbedit, for example, will open a jpeg (or anything
else for that matter) as text.

alternately, open the file from within the desired app.