The root Directory

Command ls / this command lists the root directory

[agustin@server2 agustin]$ ls /
	bin/	boot/	dev/	etc/	home/	initrd/	lib/	mnt/	opt/
	proc/	root/	sbin/	tmp/	usr/	var/

Throughout the decade, developers had tried to define standards for the file system hierarchy and for what each of these directories should be used for. But even with the efforts of all these people there are still variations among all distributions.

/ root directory of the entire system
/bin holds system executables
/sbin holds system executables and are essential for starting up the system
/boot holds the files needed during the booting process including the kernel
/devit is a special directory that holds information regarding peripherals /dev/ttys0, /dev/had, etc.
/home holds all the home directories for all users except root
/lib holds system binary libraries, shared libraries and kernel module
/opt here is where optional applications might go
/root this is the home directory for super user, do not confuse this folder with /
/tmp Here is where temporary files are stored; it is usually emptied when systems restart.
/var is where variable system files go, system logging, file locks, printer Spooling, mail spooling and many others.
/etc This directory holds almost all configuration files. As administrator you will spending most of your time tweaking settings in this folder.
/initrd this directory is used at boot time, in the initrd to perform pivot_root
/mnt This directory is used as a mount point. Here you can temporarily mount medias such as CD-ROM, zip and other file systems. Example: /mnt/windows, /mnt/floppy, mnt/cd-rom
/proc this directory is used as a kernel information access hooks, example of usage:

[agustin@server2 proc]$cat cpuinfo
[agustin@server2 agustin]$cat filesystems

/usrIt is a very large directory, holds application programs; it also has several important additional directories.
/usr/bin contains binaries executables
/usr/include This directory contains C headers with various libraries applications.
/usr/local application programs used locally