Clarify cunbatch, c7unbatch, decode and encode in documentation

[Julien-Elie]

When to use cunbatch / c7unbatch is not clear for rnews and send-uucp. Why both programs? And when the decode and encode utilities are used?

[rra]

cunbatch uses old-school compress (.Z) compression instead of gzip. It's probably thoroughly obsolete, but old commercial UNIX versions used to not have gzip.

c7unbatch is the same but it uses a 7-bit encoding, intended for transmission of articles over channels that aren't 8-bit clean. I think it uses some bespoke custom encoding rather than anything standard, but it's essentially the same idea as base64. decode and encode handle that encoding.

Chances are very good that all this stuff is obsolete. I don't think there are any systems that only have compress and not gzip these days, nor do I think there are any transport mechanisms used even for UUCP that aren't 8-bit clean. That said, it's possible someone is still using cunbatch because it used to be the default and you can configure gzip to understand it.

[Julien-Elie]

We may then be able to just declare c7unbatch obsolete, and remove the decode, encode and c7unbatch stuff in a future major INN release.

And I also propose to remove cunbatch at the same time as c7unbatch.

[mburmester]

There are situations when these are needed, like when feeding old bbs systems or things like crosspoint on MS-DOS. You can of course argue that thats all old and obsolete technology, but then again uucp is not the freshest thing ever but still comes in handy sometimes.

[Julien-Elie]

Thanks for your feedback @mburmester.
I'll then just add a note in the send-uucp documentation to explain their still possible use cases in some rare and obsolete situations.