Re: idempotent (was Re: exif --remove not idempotent, and a Debian man page bug)

[Emanuel Berg <incal@dataswamp.org>]

hede wrote:

> Meanwhile, I do think my description was not correct.
> Sorry for that. But probably the tool matches the
> definition, if it writes the same data in the second run.
> ;-)

OK, we apply idempotent on programming and you'll see this is
indeed idempotent or should be, but it isn't, either it's
a bug or I use it the wrong way.

Observe ... the question is

                         ( f.jpg  (metadata present and removed)
REMOVE_METADATA(f.jpg) = { 
                         ( f.jpg  (metadata not present, do nothing)


Okay, we apply again

REMOVE_METADATA(REMOVE_METADATA(f.jpg))

See? Result is again f.jpg and f.jpg has no metadata.

Do it again etc ...

It's idempotent!

Question: how do I use exif in the above described way?

TIA <3

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