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Date: Sun, 22 Mar 2020 18:05:04 +0000
From: Tony Finch <dot@dotat.at>
To: Dave Horsfall <dave@horsfall.org>
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Subject: Re: [TUHS] The most surprising Unix programs
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Dave Horsfall <dave@horsfall.org> wrote:
>
> I have the Towers of Hanoi written in sendmail.cf, meaning that Sendmail is
> Turing-complete :-)  I can't remember who wrote it.

Jonathan Chin: http://www.jhnc.org/hanoi/sendmail-cf.html

It's really easy to fall into the Turing tar-pit, if you have a loop
around regex-based rewriting - and unix mailers often have routing logic
that includes features for rewriting an address and re-routing it.

Tony.
-- 
f.anthony.n.finch  <dot@dotat.at>  http://dotat.at/
Thames, Dover: East or southeast 5 to 7, occasionally 4 later. Slight or
moderate. Fair. Good.