Linux Directory Structure
/ – Root : The Root Directory is a top level directory in Linux filesystem,It is the directory in which all other directories, including their sub directories, and files resides.Everything begin here in the Linux filesystem.
/bin : The bin directory, where many utilities or commands are stored.The bin directory contains several useful commands that are use to both the system administrator as well as non-privileged users. It usually contains the shells like bash, csh, etc. and commonly used commands like cp, mv, rm, cat, ls etc.
/boot : This directory contains everything required for the boot process.Such as System.map ,grub.conf, config,vmlinuz etc
/dev : This is a directory that contain device nodes.In this directory everything is a file.This is a directory where kernel maintains a list of all devices.
/etc : This directory contains all of the system configuration files.A ‘configuration file’ is a local file used to control the operation of a program, it must be static and cannot be an executable binary.this directory contains several file such as /etc/passwd,/etc/shadow,/etc/fstab,/etc/inittab etc
/home : Linux is a multi-user environment so each user is also assigned a specific directory that is accessible only this user and the system administrator./home directory can be used for storing downloads, compiling, installing and running programs,your mail, your collection of image or sound files etc.
/lib : The /lib directory contains kernel modules and shared libraries needed to boot the system and run the commands in the root filesystem. These are similar to DLLs in Windows.
/lost+found : Each formatted partition or device using a Linux filesystem,such as ext3, will have this directory. It is used in the case of a partial recovery from a filesystem corruption event. Sometimes your system is crash or a power failure might take the machine down. Fsck will go through the system and try to recover any corrupt files that it finds. The result of this recovery operation will be placed in this directory.
/media : /media directory contain the mount points for removable media such as USB drives, CD-ROMs, etc. that are mounted automatically at the insertion.
/mnt : The /mnt directory contains mount points for removable devices.Generally Mounting is the process by which you make a filesystem available to the system. After mounting your files will be accessible under the mount-point. This directory usually contains mount points or sub-directories where you mount your USB Drive and your CD.
/opt : This directory is reserved for all the optional software and add-on packages that are not part of the default installation. such as OpenOffice,netscape communicator.All third party applications should be installed in this directory.
/proc : /proc is a virtual filesystem maintained by the Linux kernel. It’s sometimes referred to as a process information pseudo-file system. It doesn’t contain ‘real’ files but run-time system information e.g. system memory, devices mounted, hardware configuration, etc.
/root : This is the home directory for the root account.
/sbin : This directory contains system binaries and those used for system maintenance and/or administrative tasks.
/tmp : This directory contains mostly files that are required temporarily at the execution currently running programs.On most systems, this directory is cleared out at boot or at shutdown by the local system.
/usr : The /usr directory tree is likely the largest one on a Linux system. This is one of the most important directories in the system. It contains all the user binaries, their documentation, libraries, header files, etc. X and its supporting libraries can be found here. User programs like telnet, ftp, etc. are also placed here. It contains all the programs and support files used by regular users.
/var : /var directory contains variable data like system logging files, mail and printer spool directories etc.