Ubuntu Filesystem Structure

Sounds strange right? Well yes it does if you come from a windows environment, where the entire operating system is consolidated onto a single drive. However, with linux and the ability to mount devices as directories, it gives the end user much greater flexibility in splitting up their operating system over several drives or partitions. Here we go

/

This is the root folder, all other folders come under root.. think of it as C: in a Windows context. The contents of the root filesystem must be adequate to boot, restore, recover, and/or repair the system.

/bin

This folder contains all the user-essential binaries (programs) that are needed to administer and run your linux system, delete this folder and your system is broken. It contains commands that may be used by both the system administrator and by users, but which are required when no other filesystems are mounted.

/boot

This folder contains configuration files and other necessary files that are needed by the bootloader. Thus /boot stores data that is used before the kernel begins executing user-mode programs. This may include saved master boot sectors and sector map files.

/dev

This folder contains special or device files. Be careful while working with it. Look through this directory and you should hopefully see hda1, hda2 etc. which represent the various partitions on the master drive of the system. It is a very interesting directory that highlights one important aspect of the Linux filesystem – everything is a file or a directory.

/etc

This folder contains all the configuration files used by the system, you can also start and stop services from here. It contains the following :
opt – Configuration for /opt
X11- Configuration for the X Window system (optional)
sgml- Configuration for SGML (optional)
xml- Configuration for XML (optional)

/home

This folder contains the home folders of all the normal (non – root ) users on the system .. think of it as my documents in windows. It is clearly a site-specific filesystem & setup will differ from host to host.

/lib

This folder contains essential shared libraries and kernel modules. This directory contains those shared library images needed to boot the system and run the commands in the root filesystem, ie. by binaries in /bin and /sbin.

/media

This is a mount point for removable media. This directory contains subdirectories which are used as mount points for removeable media such as floppy disks, CDroms, thumb drives etc.

/mnt

This is a mount point for a temporarily mounted file-systems. This directory is provided so that the system administrator may temporarily mount a filesystem as needed. The content of this directory is a local issue and should not affect the manner in which any program is run.

/lost+found

Sometimes your system might crash or a power failure might take the machine down. Either way, at the next boot, a lengthy filesystem check will be done. 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.

/opt

This folder contains add on softwares. A package to be installed in /opt must locate its static files in a separate /opt/<package> or /opt/<provider> directory tree, where <package> is a name that describes the software package and <provider> is the provider’s registered name.

/sbin

This folder contains binaries that can only be run as the root user (“superuser”).

/tmp

This folder contains temporary files that are created while browsing, video buffering, system updates etc. and all the data is erased on reboot.

/usr

This folder and its subfolders contains user installed programs, utilities and libraries. Utilities used for system administration (and other root-only commands) are stored in /sbin, /usr/sbin, and /usr/local/sbin. /sbin contains binaries essential for booting, restoring, recovering, and/or repairing the system in addition to the binaries in /bin.

/var

The /var contains data that is changed when the system is running normally. It is specific for each system, i.e., not shared over the network with other computers.

/run

This directory contains all the run time data a system administrator need while working. Everything is in one place making it easy for control purposes.

/root

This folder contians the root user’s files. The root account’s home directory may be determined by developer or local preference, but this is the recommended default location.

/proc

This is a psuedo folder, that contains information about the linux kernel and hardware that is updated in realtime.

/srv

It contains data for services provided by this system. /srv contains site-specific data which is served by this system.

Ubuntu Filesystem Structure

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