Two remarks first:
- it might seem strange for newcomers from Mac OS X to choose Devuan, since MacOS itself didn't keep an original SystemV init system but is using
launchd so there's anyway a new init system to learn (if one chooses to learn about it), whatever it would have been. Usually people choosing Devuan over Debian are already knowledgeable in this field.
- Devuan's site while mentionning the availability of
non-free doesn't seem to document how to use it, probably expecting people choosing Devuan to already know.
So just find either in the file
/etc/apt/sources.list or in a file in the directory
/etc/apt/sources.list.d/ the entries about devuan with the word
main and append
contrib non-free to it. This should typically give something like:
deb http://deb.devuan.org/merged ascii main contrib non-free
deb http://deb.devuan.org/merged ascii-security main contrib non-free
Remember to choose a source provided by the distribution whenever possible to avoid FrankenDebian or here FrankenDevuan. It might be a bit misleading here, because I believe (not sure) that
devuan.org plays the role of a kind of automatic reverse proxy which can dispatch the final URL either to devuan or to debian for untouched packages.