/bin

User programs and scripts essential to system startup

/boot

Boot information, including the kernel

/dev

Device files

/etc

Host-specific configuration files

/etc/sysconfig

Stores configuration files specific to Red Hat Linux

/home

Users' home directories

/initrd

Used during boot process as a mount point for a directory containing special device drivers

/lib

Libraries, modules, and other object files

/lib/modules

Loadable kernel modules

/lost+found

Recovered data from bad clusters

/mnt

Temporarily mounted filesystems

/opt

Used to store large applications

/proc

Kernel pseudo-directory that provides access to kernel information and configuration items

/root

System administrator's home directory

/sbin

System administration programs and scripts essential to system startup

/tmp

Temporary files, which are automatically deleted by Red Hat Linux

/usr

Files needed for system operation but not needed to boot system (can be mounted read-only, except when being changed by root user)

/usr/bin

Programs and scripts not essential to system startup

/usr/dict

System dictionaries for spell checking

/usr/etc

Configuration files

/usr/games

Game files

/usr/include

C/C++ header files

/usr/kerberos

Kerberos files

/usr/lib

Libraries and kernel modules

/usr/libexec

Libraries stored in alternate formats

/usr/local

Locally defined directory tree (structure is similar to that of /usr)

/usr/sbin

System administration programs and scripts not essential to system start up

/usr/share

Shared files

/usr/share/doc

Documentation (formerly residing in /usr/doc)

/usr/share/man

Manpages

/usr/src

Source files

/usr/src/linux

Linux kernel source

/usr/X11R6

X-related files

/var

Dynamic files, such as log files and spool files

/var/arpwatch

Data used by arpwatch

/var/cache

Application cache data

/var/ftp

Data used by the FTP server

/var/gdm

Data used by the GNOME display manager

/var/kerberos

Data used by Kerberos

/var/lib

Variable state information

/var/lib/rpm

Files related to RPM

/var/local

Locally defined data

/var/lock

Lock files

/var/log

Log files and directories

/var/named

Data used by BIND (named)

/var/opt

Data used by applications in /opt

/var/run

Process IDs of running processes

/var/spool

Application spool data

/var/spool/anacron

Anacron's spool data

/var/spool/at

At's spool data

/var/spool/cron

Cron's spool data

/var/spool/fax

Fax's spool data

/var/spool/lpd

Printer queues

/var/spool/mail

Mail boxes

/var/spool/mqueue

Mail queue

/var/spool/news

USENET News spool data

/var/spool/rwho

Rwho spool data

/var/spool/samba

Samba spool data

/var/spool/slrnpull

Slrnpull spool data

/var/spool/squid

Squid spool data

/var/spool/uucp

UUCP spool data

/var/spool/uucpublic

Public UUCP spool data

/var/spool/up2date

Files used by Red Hat Update Agent

/var/tmp

Temporary files preserved between system reboots

/var/tux

Files used by Tux

/var/www

Files used by Apache

/var/yp

Files used by NIS