Comment by jcgl
1 day ago
Completely agreed. Not sure what the historical reasons for lsof and ss are, but unix tools are structurally in a hard place when it comes to having sensible defaults over the long term.
Generally speaking, you can only have sensible defaults over time if you're able to change the defaults over time. New users and new use-cases come with time, and so what constitutes a "sensible default" changes.
However (and this is a drum I like to bang[0]), because unix tools only deal in usually-text bytestreams without any higher level of abstraction, consumers of those tools end up tightly coupled with how output is presented. Without any separation between data and its representation, the (default) representation is the tool's API. To change the default representation is to make a backwards-incompatible API change. A good example of this is how ps aux truncates longer than like 7 characters.
Hah yes, I've come to unashamedly - by muscle memory since the 1990's - find myself always typing 'ps auxw[w...]', where [w...] is some arbitrary number of w's depending on how heavy my index finger feels at the moment of typing.
> change the defaults over time
however this breaks backward compatibility, as you noted. in the golden age of unix it was critical to maintain backward compatibility so that local tooling didn't magically break.
HP-UX seems to have an env var UNIX95 that affects XPG4 compliance in operation/output. Solaris always had a /usr/xpg[46] path (and /usr/ucb). GNU tools have POSIXLY_CORRECT. and so on.
I never liked using any of those because then you're on some other system, or in a break glass situation, and none of the tooling works as you expect. In the today world of a near monoculture of linux, it's fine I guess. And there's no reason today that complex commands like `ss` shouldn't be controllable via env var.
love your blog, thanks for the link.
> love your blog, thanks for the link.
Thank you!
Configuring configuration via env var is a good historical example. I think that especially works nicely when you Buy An Operating System. You know, one that is created and provided by A Vendor. In principle, the vendor can architect a unified metaconfiguration system, e.g. one or several env vars that align behavior to a standard.
But I dunno if it would work so well to to hypothetically apply that tactic to a modern bazaar-based OS like Linux. Distros do amazing, valuable work to unify things, but modern Linux is basically a zillion software packages in a trench coat. So either the distro carries a zillion patches to have a few env vars, or the distro carries no patches and there are a zillion env vars. Either way, total cost of maintenance explodes.
Maybe when people say "text is the universal interface," they really mean that once you've released a textual interface, the interface becomes universal, unchanging for all time.