Linux File System

A filesystem is a method and data structure that an operating system uses to keep track of files on a disk or partition in short, the way the files are organized on the disk. The word is also used to refer to a partition or disk that is used to store the files or the type of the filesystem.

1. / :
   It is the Top level root directory for all the child directories. Everything starts from the root directory, represented by /, and then expands into sub−directories instead of having so−called ‘drives’.  It is represented with forward slash (“/”).
2. /root: 
   root users home directory which is not same as ‘ /  ‘   only root users has write privilege under this directory.
3. /dev : 
   It contains devices files ,   This includes terminal devices  like /dev/sda, usb or any other devices  attached to the system.  Similar like device manager in windows.
4. /boot:
    It contains system bootable files, kernel related information and bootloader information
5. /usr:
   It contains binaries and loaders, and by default software’s are installed in /usr directory
   –> /usr/bin contains binary files for user programs ex. Awk,less,scp
   –> /usr/sbin contains binary files of system administrators ex: cron,ssh.useradd
   –> /usr/lib   contains libraries for /usr/bin and /usr/sbin
6. /var: It contains variables file information, such as
   –> system logs files will be in  /var/log
   –> databases files in /var/lib/mysql/
   –> email s in /var/mail
   –> temp files in /var/tmp 
7. /etc:  
   It contains all system configuration files information  like
   –> /etc/resolv.conf
   –> /etc/logrotate.conf
   –> /etc/hosts
8. /home:
   it is home directory for other users except root user , other users to store their personal information and provides working environment for users.
   –> /home/Rajkumar
   –>/home/ctrls
9. /opt:
   It is optional directory for users, consists of third party software’s.
10. /media :
      It contains all removable media devices like cd-rom, pen drive
11. /mnt: 
    It is temporary mount directory where sysadmins can mount file systems ,and it is empty by default.
12. /proc :
    It contains information about system process,this is virtual file system with text information about system resources. 
    –> Ex:  /proc/meminfo, /proc/cpuinfo, /proc/uptime
13. /bin: 
     It contains binary executables and contains commands used   by all users ex. Ls , ping ,grep cp
14. /sbin:      
    It is just like /bin this also contains binary executables but commands under this directoy are used by system administartors for system maintenance purpose.
    –> Ex: fdisk, iptables, reboot, ifconfig
15. /lib: 
    It contains library files that supports the binaries located under /bin and /sbin