Linux file system hierarchy

If you look at the Linux file hierarchy, you find the following :

/bin - Common binaries

/sbin - Binaries used for system administration are placed here.

/boot - Static files of the boot loader. Usually it contain the Linux kernel, Grub boot loader files and so on.

/dev - Device files such as your CD drive, hard disk, and any other physical device. 

In Linux/Unix, the common premise is that everything is a file.

/home - User HOME directories are found here. In unices like FreeBSD, the HOME directories are found in /usr/home. And in Solaris it is in /export. So quite a big difference here.



/lib - Essential shared libraries and kernel modules.

/mnt - Temporary mount point useful for when you insert your USB stick and it gets mounted under /mnt. Though in Ubuntu and the likes, it is usually mounted under /media.

/var - Variable data, such as logs, news, mail spool files and so on which is constantly being modified by various programs running on your system.

/tmp - Temporary files are placed here by default.

/usr - The secondary hierarchy which contain its own bin and sbin sub-directories.

/etc - Usually contain the configuration files for all the programs that run on your Linux/Unix system.

/opt - Third party application packages which does not conform to the standard Linux file hierarchy can be installed here.

/srv - Contains data for services provided by the system.

And of course there is the /proc directory which does not actually reside on the disk.

The file system hierarchy standard [FSHS] explains /etc as follows :

The /etc hierarchy contains 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.

It further goes on to say :

No binaries may be located under '/etc'. And the following directories, or symbolic links to directories are required in /etc:

• opt Configuration for /opt
• X11 Configuration for the X Window system (optional)
• sgml Configuration for SGML (optional)
• xml Configuration for XML (optional)

While this is the long and short of the matter, some believe that '/etc' is indeed an acronym and stands for "Editable Text Configuration". Oh well, the media is still not out with the verdict.