Re: Debian switchable MTA mechanism
On Wed 17 Feb 2021 at 07:49:57 (+0800), Kevin Shell wrote:
> On Wed, Feb 17, 2021 at 07:47:51AM +0800, Kevin Shell wrote:
> > On Wed, Feb 17, 2021 at 07:39:15AM +0800, Kevin Shell wrote:
> > > On Tue, Feb 16, 2021 at 04:38:06PM -0600, David Wright wrote:
> > > > On Tue 16 Feb 2021 at 17:48:25 (+0800), Kevin Shell wrote:
> > > >
> > > [...]
> > > > > Isn't Debian already has a /etc/alternatives/ mechanism?
> > > >
> > > > AIUI all the targets of /etc/alternatives are all installed at the
> > > > same time, and can be simultaneously run without conflicting with
> > > > each other. The links merely select which target is run (and
> > > > documented) by invoking a name, like "www-browser" (→ lynx for me),
> > > > "awk" (gawk) or "rename" (the Perl one). I might be running firefox,
> > > > mawk and rename.ul (by their specific name) at the same time as the
> > > > "default" versions.
> > > >
> > > I asked this question because on my laptop there's an alternatives system
> > > that can keep several programs providing the same or similar functions
> > > at the same time.
> > > Debian also has an alternatives system but doesn't allowed to install
> > > multiple MTAs.
> > >
> > > https://github.com/fedora-sysv/chkconfig/blob/master/alternatives.c
> > > $ dnf info alternatives
> > > Name : alternatives
> > > Summary : A tool to maintain symbolic links determining default commands
> > > URL : https://github.com/fedora-sysv/chkconfig
> > > License : GPLv2
> > > Description : alternatives creates, removes, maintains and displays information about
> > > : the symbolic links comprising the alternatives system. It is possible
> > > : for several programs fulfilling the same or similar functions to be
> > > : installed on a single system at the same time.
> > >
> > besides BSD systems also have a similar system call mailwrapper
> called
> > http://man.openbsd.org/mailwrapper.8
AIUI (and I'm not one to be playing these tricks), it doesn't seem to
do more than using, say,
. Debian's alternatives to create a dummy package that satisfies apt's
dependencies, and
. installing your favoured foreign replacement in, say, /opt.
Again, I'll pass on looking for documentation on switching MTAs
using mailwrapper.
Cheers,
David.
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