>>>> I'm still trying to figure out the meaning of all the directories in
>>> linux. bin makes sense for binaries... What's /usr mean? and /usr/local?
>>> I'm thinking sbin is binaries for the superuser or root, right? Of course,
>>> all the configs end up in /etc instead of in the directory where the
>>> application is... And they log stuff to /var/log . So... stuff's scattered
>>> somewhat. But what's the difference between /usr/local and /usr?

/ -> default system things (operating system, basic utilities, boot 
system)

/usr -> application things to be used by user mode programs and 
utilities

/usr/local/ -> as above, but customized to this machine installation 
instance, sometimes moved to /opt or /var by certain distributions

/var/ -> all of the above, but especially files that must be open for 
read-write (all of the directories above can be mounted read-only on a 
properly configured system, as they will never be written to excepting 
during software installations).

~/ -> per-user binaries, libraries and so on, specific to each user.

The basic structure of subdirectories /lib /bin /sbin /etc is repeated 
under each of these as needed.

The same thing applies for configuration files. 'Default' libraries and 
so for 'program' on are stored under /lib/program/... or 
/usr/lib/program/..., the main (boot time) configuration files are in 
/etc/ (and /usr/etc and /usr/local/etc) and the per-user configs are in 
dot-files in the user's home directories (e.g. ~/.programrc).

Configuration files are slightly different. Typically, most 'properly' 
written programs will look at configs in the order:

$PWD/.programrc -> a config file in the present directory
~/.programrc -> a config file in the user home directory
/etc/program.conf -> a system wide configuration file
/usr/local/lib/program/program.conf.default -> the default configuration

This allows for a lot of flexibility in configuration. The exact names 
and the meaning of reading another, superseding, config file depend on 
the program.

Also the environment variables PATH and MANPATH would be set 
differently during various tasks. PATH sets the serach order for 
directories with executables and MANPATH the same for manual pages.

So f.ex. a user who uses the ~/bin ~/man  system to install binaries for 
himself (not requiring admin privileges for this) would set 
PATH=~/bin:$PATH and MANPATH=~/man:$MANPATH for most operations.

Peter
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