I think that I will recommend Void Linux to you.

The reasons are as follows :
1. rolling release as Gentoo and Arch.
2. use runit as init system.
3. Its package manager, xbps, is easy and quick to install/update/remove software.


On Fri, Nov 24, 2017 at 9:47 AM, Nikos Chantziaras <realnc@gmail.com> wrote:
On 24/11/17 00:01, Wols Lists wrote:
On 23/11/17 18:45, Nikos Chantziaras wrote:
On 23/11/17 19:11, Helmut Jarausch wrote:

I'd like to recommend a Linux distribution to someone who needs an as
simple Linux distribution as possible.
Since I am going to help that person from time to time, it should be
as similar as possible to Gentoo.
 [...]

Arch Linux is similar. Just imagine you have "emerge", except there's
only binary packages. When you install it initially, you're left on the
command line with nothing installed except base packages, much like Gentoo.

How close is Slackware to that description?
 [...]

I'd say not close at all. Slackware uses pretty outdated software and is not rolling release.

Arch Linux on the other hand, like Gentoo, does not have releases. You install it once and the upgrades are pretty much identical to Gentoo.