Linux Directory Structure
From NeoWiki
The directory structure of Linux/other Unix-like systems is very intimidating for the new user, especially if he/she is migrating from Windows. In Windows, almost all programs install their files (all files) in the directory named: `Program Files.’ Such is not the case in Linux. The directory system categorises all installed files. All configuration files are in /etc, all binary files are in /bin or /usr/bin or /usr/local/bin. Here is the entire directory structure along with what they contain:
/ - Root directory that forms the base of the file system. All files and directories are logically contained inside the root directory regardless of their physical locations. /bin - Contains the executable programs that are part of the Linux operating system. Many Linux commands, such as cat, cp, ls, more, and tar, are locate in /bin /boot - Contains the Linux kernel and other files needed by LILO and GRUB boot managers. /dev - Contains all device files. Linux treats each device as a special file. All such files are located in /dev. /etc - Contains most system configuration files and the initialisation scripts in /etc/rc.d subdirectory. /home - Home directory is the parent to the home directories of users. /lib - Contains library files, including loadable driver modules needed to boot the system. /lost+found - Directory for lost files. Every disk partition has a lost+found directory. /media - Directory for mounting files systems on removable media like CD-ROM drives, floppy disks, and Zip drives. /mnt - A directory for temporarily mounted filesystems. /opt - Optional software packages copy/install files here. /proc - A special directory in a virtual filesystem. It contains the information about various aspects of a Linux system. /root - Home directory of the root user. /sbin - Contains administrative binary files. Commands such as mount, shutdown, umount, reside here. /srv - Contains data for services (HTTP, FTP, etc.) offered by the system. /sys - A special directory that contains information about the devices, as seen by the Linux kernel. /tmp - Temporary directory which can be used as a scratch directory (storage for temporary files). The contents of this directory are cleared each time the system boots. /usr - Contains subdirectories for many programs such as the X Window System. /usr/bin - Contains executable files for many Linux commands. It is not part of the core Linux operating system. /usr/include - Contains header files for C and C++ programming languages /usr/lib - Contains libraries for C and C++ programming languages. /usr/local - Contains local files. It has a similar directories as /usr contains. /usr/sbin - Contains administrative commands. /usr/share - Contains files that are shared, like, default configuration files, images, documentation, etc. /usr/src - Contains the source code for the Linux kernel. /var - Contains various system files such as log, mail directories, print spool, etc. which tend to change in numbers and size over time. /var/cache - Storage area for cached data for applications. /var/lib - Contains information relating to the current state of applications. Programs modify this when they run. /var/lock - Contains lock files which are checked by applications so that a resource can be used by one application only. /var/log - Contains log files for differenct applications. /var/mail - Contains users’ emails. /var/opt - Contains variable data for packages stored in /opt directory. /var/run - Contains data describing the system since it was booted. /var/spool - Contains data that is waiting for some kind of processing. /var/tmp - Contains temporary files preserved between system reboots.