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