How does the linux file system work ?

Linux file structure starts from the root / directory and expands into sub-directories.

File systems

Root "/"

Kernel needs a root file system to mount at start up.

The root directory usually does not have the critical files.

E.g.  

/bin  Commands needed during boot up

/etc  Config files

/lib  Shared libraries

/usr

It is large as it contains the executable files to be shared amongst different machines.

Sub directories include :

/usr/bin 

/usr/include 

/usr/lib 

/usr/local  for local executable

/var

It is specific to local systems where the data keeps changing.

The sub directories includes :

/cache/man  A cache for man pages

/games  Any variable data belong to games

/lib  Files that change

/log  Log from different programs

/tmp  for temporary files

/home

This file system differs from host to host.

User specific configuration files for applications are stored in the user's home directory in a file. UNIX creates directories for all users directory.

E.g /home/my_name

Once the user is logged in ; he is placed in his home directory.

/proc

It is created by the kernel in its memory to provide information about the system.

Few of the Directories include :

/1  Directory with information about process num 1, where 1 is the identification number

/cpuinfo  information about CPU

/devices  information about devices installed

/filesystem  File systems configured

/net   Information about network protocols

/mem  Memory usage