Below is an explanation of the Linux directory structure, and what everyone is used for. Hope that it helps.
In the Linux operating system, all filesystems are contained within
one directory hierarchy. The root directory is the top level
directory, and all its subdirectories make up the directory hierarchy.
This differs to other operating systems such as MS-Windows which
applies a separate hierarchy for each device and partition.
/bin -- binary applications (most of your executable files)
/boot -- files required to boot (such as the kernel, etc)
/dev -- your devices (everything from drives to displays)
/etc -- just about every configuration file for your system
/etc/profile.d -- contains scripts that are run by /etc/profile upon
/etc/rc.d -- contains a number of shell scripts that are run on bootup
at different run levels. There is also typically an rc.inet1 script to
set up networking (in Slackwar), an rc.modules script to load modular
device drivers, and an rc.local script that can be edited to run
commands desired by the administrator, along the lines of autoexec.bat
/etc/rc.d/init.d -- contains most of the initialization scripts
themselves on an rpm-based system.
/etc/rc.d/rc*.d -- where "*" is a number corresponding to the default
run level. Contains files for services to be started and stopped at
that run level. On rpm-based systems, these files are symbolic links
to the initialization scripts themselves, which are in
/etc/skel -- directory containing several example or skeleton
initialization shells. Often contains subdirectories and files used to
populate a new user's home directory.
/etc/X11 -- configuration files for the X Window system
/home -- locally stored user files and folders
/lib -- system libraries (similar to Program Files)
/lost+found -- lost and found for lost files
/media -- mounted (or loaded) devices such as cdroms, digital cameras,
/mnt -- mounted file systems
/opt -- location for “optionally” installed programs
/proc -- dynamic directory including information about and listing of
/root -- “home” folder for the root user
/sbin -- system-only binaries (see /bin)
/sys -- contains information about the system
/tmp -- temporary files
/usr -- applications mainly for regular users
/var -- mainly logs, databases, etc.
/usr/local/bin -- the place to put your own programs. They will not be
overwritten with upgrades.
/usr/share/doc -- documentation.1