On Sun, Oct 08, 2017 at 08:02:42PM +0200, Antony Stone wrote:
> On Saturday 07 October 2017 at 14:20:18, Renaud (Ron) OLGIATI wrote:
>
> > Is there a way to move from Devuan Jessie to Debian Jessie without catching
> > the systemd pox ?
>
> Depending on whether you use any applications which have dependencies on
> systemd, you can certainly run Debian Jessie without systemd. It uses systemd
> by default, but it's trivial to remove and replace with sysvinit, provided you
> haven't installed anything which requires systemd. If you're starting from
> Devuan, this is unlikely to be the case...

Generally, all desktop environments but hardly anything else in Debian
Jessie require systemd for an important part of operation.

For this, you have two options: systemd as init (meh): package systemd-sysv,
or systemd as a partial infection: package systemd-shim; both of these
require the actual systemd package but run it differently.

To get rid of systemd, you'd need to rebuild affected parts (the Utopia
stack). I've done so in the past but my package set for jessie is left
unmaintained (all my GUI machines are on unstable thus buster, two releases
ahead).

> I've never tried migrating a Devuan Jessie system to Debian Jessie, but I have
> done it the other way around, and this is what the dist-upgrade part did for
> me:
>

> # apt-get dist-upgrade
> Reading package lists... Done
> Building dependency tree       
> Reading state information... Done
> Calculating upgrade... Done
> The following packages will be REMOVED:
>   systemd-sysv
> The following NEW packages will be installed:
>   e2fsprogs init libfdisk1 libss2 sysvinit-core
> The following packages will be upgraded:
>   base-files bsdutils debian-archive-keyring init-system-helpers initscripts 
> libblkid1 libmount1 libsmartcols1 libuuid1 lsb-base lsb-release mount sysv-rc 
> sysvinit-utils util-linux uuid-runtime
> 16 upgraded, 5 newly installed, 1 to remove and 0 not upgraded.

>
> So, only 5 new packages got installed, and 16 upgraded.
>
> It seems reasonable to me to assume that much the same would be the case for a
> Devuan Jessie -> Debian Jessie "upgrade". I'd say it's certainly worth a
> backup and a try.

It won't work as Devuan packages have higher version numbers than their
Debian counterparts. It might work with a mere "-t jessie" on the apt line,
but it's likely you'd need the big hammer of pin > 1000:

.--====[ /etc/apt/preferences ]
Package: *
Pin: release a=oldstable
Pin-Priority: 1001
`----

This forces a downgrade of all packages.

Meow!
-- 
⢀⣴⠾⠻⢶⣦⠀ We domesticated dogs 36000 years ago; together we chased
⣾⠁⢰⠒⠀⣿⡁ animals, hung out and licked or scratched our private parts.
⢿⡄⠘⠷⠚⠋⠀ Cats domesticated us 9500 years ago, and immediately we got
⠈⠳⣄⠀⠀⠀⠀ agriculture, towns then cities.     -- whitroth on /.