For information on how to run sway/wayland see this thread:
https://forum.obarun.org/viewtopic.php?id=1392
use cower or pacopts to download the aur pkg greetd
https://aur.archlinux.org/cgit/aur.git/tree/PKGBUILD
cd to greetd
or
cd /tmp
mkdir greetd
cd greetd
wget https://aur.archlinux.org/cgit/aur.git/tree/PKGBUILD?h=greetd
wget https://aur.archlinux.org/cgit/aur.git/tree/greetd.pam?h=greetd
edit PKGBUILD
1 remove systemd from the dependencies
depends=(systemd pam)
depends=(pam)
2 Use a comment # or remove these two lines:
# install -Dm644 "$srcdir/greetd-$pkgver/greetd.service" \
# "$pkgdir/usr/lib/systemd/system/greetd.service"
(you can change the package number to 2 from 1 pkgrel=1 --> pkgrel=2 so it is not confuses in your cache with the AUR pkg.)
3 save PKGBUILD and exit
4 make sure you have the greetd.pam file in your directory and it looks like this
# %PAM-1.0
auth required pam_securetty.so
auth requisite pam_nologin.so
auth include system-local-login
account include system-local-login
session include system-local-login
install the pkg produced:
% sudo pacman -S git rust scdoc pam
Note which of these were not already installed so you can remove them at the end.
% makepkg
% sudo pacman -U greetd*.pkg.tar.xz
% sudo mv greetd*.pkg.tar.xz /var/cache/pacman/pkg/
Maybe Eric or JM can contribute an install line to be added to the PKGBUILD with obsysusers to add greeter to the video group.