On Sat, 18 Feb 2012 20:44:13 +1000, Da Rock wrote:

There's lots of philosophy, tradition and vanished differentiation in this field. The manpage "man hier" provides a good explaination for the layout chosen for FreeBSD. However, there are questions that may arise:

What kind of programs? Those called by users, by the system, or by other programs (see libexec)?

What's the difference between /bin and /sbin, same for /usr/bin and /usr/sbin? Could they maybe be merged when their functionality is similar and they reside on the same partition (file system) anyway?

The /etc directory - "editable text configuration" :-) - historically also contained binaries like /etc/mount or /etc/GETTY. Depending on its location, one can assume that it controls OS things only. Wrong. In many cases, /etc/rc.conf also contains settings for enabling services installed by ports. Even though FreeBSD can use /etc/rc.conf.local (has been known in OpenBSD for non-OS setup stuff), most things are found in the system-wide file. But the corresponding start scripts are in /usr/local/etc/rc.d. Why no /usr/local/etc/rc.conf? But as rc.conf is just a file to associate variables with names, there's no problem if they are defined, but not used (e. g. in a limited system state after encountering a problem)...

Luckily, most software installed from ports keeps its settings out of /etc and uses /usr/local/etc instead. Having _known_ locations for settings makes it easy to back them up.

How about X on desktops? /etc/X11 is the common location for config files (if used), but per deduction, they should be in /usr/local/etc/X11 as X is a port, not a part of the OS. What about the configuration of xdm? Why isn't it stored in some /usr/local/etc subtree, but instead /usr/local/lib/X11/xdm/ is used?

This short list is just to mention the loads of philosophy hidden within the system. :-)