Wait what? Why prefix length limits? Linux paths can be 4096 bytes long, I can't imagine y'all are hitting that?

Pouring a bottle requires rewriting paths embedded in binaries, which results in a cap.

Postgres is an example of this: the various directories are set at build time.

I’d imagine they’re live updating the library paths in the binary headers, so anything shorter or equal to what they’re using is a simple rewrite, but longer is more complex.

Ah. That makes sense.

It's so annoying how deeply UNIX packaging philosophy assumes that installation directories are something you hard-code at build time.

The present is built mostly on layers of the long-past :)

It makes me think of when Arch merged /usr/bin and sbin with /bin and sbin. Having them split made sense in a ton of scenarios that used to be very common, but increasingly the split was vestigial for most users.

Yea, my understanding is that the split between / and /usr used to be more or less: the drive they used for / ran out of space, so they mounted another drive as /usr. As a consequence, / became where you put stuff that was essential during early boot, while /usr was where you put everything else.

But these days, "early boot" is handled by initramfs and we've all got drives large enough to not need the split anyway.

It was also useful for many machines to share a single /usr over NFS