Conocer la jerarquía estándar de un sistema de ficheros de *nix es algo básico, pero también es normal que desconozcamos para que se utiliza un determinado directorio, qué es lo que se almacena en él, etc.
Como ya indiqué en un artículo ayá por 2011, hay formas de encontrar ayuda en Linux, BSD y Unix sin necesidad de acudir a Internet, y que por consiguiente nos pueden salvar cuando estamos trabajando en una máquina sin salida a Internet. En este caso, si en algún momento necesitamos información o tenemos curiosidad por conocer la jerarquía del sistema de ficheros *nix o información concreta de un directorio específico, tal solo tenemos que consultar la página man de «hier» para visualizar toda la información que necesitamos del Filesystem Hierarchy Standard (FHS). Funciona en Debian, RHEL, CentOS, OS X, HP-UX, etc:
$ man hier
Eh voilá…
DESCRIPTION
A typical Linux system has, among others, the following directories:
/ This is the root directory. This is where the whole tree starts.
/bin This directory contains executable programs which are needed in single user mode and to bring the system up or repair it.
/boot Contains static files for the boot loader. This directory only holds the files which are needed during the boot process. The map installer and configuration files should go to /sbin and /etc.
/dev Special or device files, which refer to physical devices. See mknod(1).
/etc Contains configuration files which are local to the machine. Some larger software packages, like X11, can have their own subdirectories below /etc. Site-wide configuration files may be placed here or in /usr/etc.
Nevertheless, programs should always look for these files in /etc and you may have links for these files to /usr/etc.
/etc/opt
Host-specific configuration files for add-on applications installed in /opt.
/etc/sgml
This directory contains the configuration files for SGML and XML (optional).
/etc/skel
When a new user account is created, files from this directory are usually copied into the user's home directory.
/etc/X11
Configuration files for the X11 window system (optional).
/home On machines with home directories for users, these are usually beneath this directory, directly or not. The structure of this directory depends on local administration decisions.
/lib This directory should hold those shared libraries that are necessary to boot the system and to run the commands in the root file system.
/media This directory contains mount points for removable media such as CD and DVD disks or USB sticks.
/mnt This directory is a mount point for a temporarily mounted file system. In some distributions, /mnt contains subdirectories intended to be used as mount points for several temporary file systems.
/opt This directory should contain add-on packages that contain static files.
/proc This is a mount point for the proc file system, which provides information about running processes and the kernel. This pseudo-file system is described in more detail in proc(5).
/root This directory is usually the home directory for the root user (optional).
/sbin Like /bin, this directory holds commands needed to boot the system, but which are usually not executed by normal users.
/srv This directory contains site-specific data that is served by this system.
/tmp This directory contains temporary files which may be deleted with no notice, such as by a regular job or at system boot up.
/usr This directory is usually mounted from a separate partition. It should hold only sharable, read-only data, so that it can be mounted by various machines running Linux.
[...]