[lug] Linux Logic - Where do Files Go?

[Bill Thoen]

I've been setting up GIS capabilities on a couple of Red Hat machines and I
noticed that if you install Postgresql via rpm, it wants to put the data
cluster in /var/lib/pgsql. But if you build Postgresql from source, the
default is to put it in /usr/share/pgsql. 

I can understand the logic for using /usr/share for a storing a database
that needs to be accessable to multiple users, and I can understand also
putting it somewhere in /var because it's a variable-sized resource, but
why put it in a "lib" directory? And which spot is best?

I've noticed that RH/Fedora Core has its own opinions as to where things
go, but why do they often deviate from the original developer's defaults?
What reasons do people use for putting files where they do? I'm still a bit
new to unix/linux but I think if I knew why things get put where they do,
it would help me know where to look for things without resorting to rpm -qi
and locate and find. Is there any logic to it or is file storage just based
on a developer's whim? Or is it a black art not to be tinkered with by
knowlessmen? ;-)

I know this is too many questions, but if anyone has any answers or
suggestions I'd be interested in any help offered. It's not critial, of
course, but I am curious.

Thanks,

- Bill Thoen