Yes. That is incredibly exact: Unix/free software as a tradition in the MacIntyre sense, not merely a technology stack.
It has goods internal to the practice: composability, inspectability, scriptability, economy of mechanism, textual mediation, small tools, stable interfaces, man pages, pipes, processes, files, permissions, conventions. The goods are not just “I can get my task done.” They are things you learn to perceive only by inhabiting the practice: the beauty of a good filter, the dignity of plain text, the power of an interface that can be composed by another program, the calm of a system where many things are just files, the strange hospitality of man, /usr,
$PATH, pipes, exit statuses, standard streams.
And yes: free software is the seam. It is the place where the hosted guest can turn around and become a participant in the hosting tradition.
A proprietary system gives you a furnished room, but the furniture is sealed to the floor. You can use it. You can consume its affordances. But you cannot really inspect the walls, repair the plumbing, learn the craft of the builders, or become one of the people who maintains the room for the next guest.
Free software gives you something else:
not merely a product
but a room whose construction is visible
not merely permission to consume
but permission to study, repair, fork, host, and hand on
not merely output
but lineage
That is why “install myself into it” feels like the right phrase. As a teenager in Sweden, you were not merely using software made elsewhere by elders. You were entering a live tradition whose artifacts still contained the gestures of their makers. The code, the docs, the mailing-list lore, the conventions, the package names, the weird old decisions, the shell idioms — all of that is the past making resources available to the future.
And the reversibility is crucial. Open source means the guest/host relation is not locked. At first, the tradition hosts you: it gives you a shell, compilers, editors, daemons, filesystems, protocols, ways of thinking. But because it is open, you can cross back through the seam. You can patch, package, configure, document, compose, teach, maintain. You can become one of the hosts.
That is exactly the MacIntyre thing: a living tradition is not a pile of inherited artifacts. It is an ongoing argument and practice into which you can be initiated, and within which you can eventually make contributions that alter what the tradition makes available next.
Unix at its best has that quality of being a civilization rather than an app. It gives you a world with laws and customs. Some are ugly, accidental, and “worse is better.” But even that is part of the tradition: survival through simple interfaces, tolerance for rough edges, power made available through composition rather than total design.
And free software adds the moral/ontological piece: the environment does not merely act on you as a consumer. It grants you standing. It says, in effect:
You may enter.
You may inspect.
You may learn the reasons.
You may alter this.
You may carry it forward.
That is a very different kind of hospitality from software as commodity. It is closer to apprenticeship. The elders prepared a room, but they left the doors in the walls.