Linux File System Structure

Linux File System Structure

/ - Root directory that forms the base of the file system. All files and directories are logically contained inside the root directory regardless of their physical locations. 

/bin - Contains the executable programs that are part of the Linux operating system. Many Linux commands, such as cat, cp, ls, more, and tar, are locate in /bin 

/boot - Contains the Linux kernel and other files needed by LILO and GRUB boot managers. 

/dev - Contains all device files. Linux treats each device as a special file. All such files are located in /dev. 

/etc - Contains most system configuration files and the initialization scripts in /etc/rc.d subdirectory.

 
/home - Home directory is the parent to the home directories for users.
/lib - Contains library files, including loadable driver modules needed to boot the system.

 
/lost+found - Directory for lost files. Every disk partition has a lost+found directory. 

/media - Directory for mounting files systems on removable media like DVD-ROM drives, flash drives, and Zip drives. 

/mnt - A directory for temporarily mounted filesystems (ie Backup Software). 

/opt - Optional software packages copy/install files here. 

/proc - A special directory in a virtual memory filesystem. It contains the information about various aspects of a Linux system.

 
/root - Home directory of the root user. 

/run - On newer versions. Gives applications a standard place to store transient files they require like sockets and process IDs. 

/sbin - Contains administrative binary files. Commands such as mount, shutdown, umount, reside here. 

/selinux - If your Linux distribution uses SELinux for security. Contains special files used by SELinux. 

/srv - Contains data for services (HTTP, FTP, etc.) offered by the system. 

/sys - A special directory that contains information about the devices, as viewed by the Linux kernel. 

/tmp - Temporary directory which can be used as a scratch directory (storage for temporary files). The contents of this directory are cleared each time the system boots. 

/usr - Contains subdirectories for many programs such as the X or GUI Window System. 

/usr/bin - Contains executable files for many Linux commands. It is not part of the core Linux operating system. 

/usr/include - Contains header files for C programming languages 

/usr/lib - Contains libraries for C programming languages. 

/usr/local - Contains local files. It has a similar directories as /usr contains.

 
/usr/sbin - Contains administrative commands. 

/usr/share - Contains files that are shared, like, default configuration files, images, documentation, etc. 

/usr/src - Contains the source code for the Linux kernel. 

/var - Contains various system files such as log, mail directories, print spool, etc. which tend to change in numbers and size over time. 

/var/cache - Storage area for cached data for applications. 

/var/lib - Contains information relating to the current state of applications. Programs modify this when they run. 

/var/lock - Contains lock files which are checked by applications so that a resource can be used by one application only. 

/var/log - Contains log files for different applications. 

/var/mail - Contains users' emails sent by system or server. 

/var/opt - Contains variable data for packages stored in opt directory. 

/var/run - Contains data describing the system since it was booted. 

/var/spool - Contains data that is waiting for some kind of processing. 

/var/tmp - Temporary files preserved between system reboots.

 

 

1. / – Root

• Every single file and directory starts from the root directory.
• Only root user has write privilege under this directory.
• Please note that /root is root user’s home directory, which is not same as /.

2. /bin – User Binaries

• Contains binary executables.
• Common linux commands you need to use in single-user modes are located under this directory.
• Commands used by all the users of the system are located here.
• For example: ps, ls, ping, grep, cp.

3. /sbin – System Binaries

• Just like /bin, /sbin also contains binary executables.
• But, the linux commands located under this directory are used typically by system aministrator, for system maintenance purpose.
• For example: iptables, reboot, fdisk, ifconfig, swapon

4. /etc – Configuration Files

• Contains configuration files required by all programs.
• This also contains startup and shutdown shell scripts used to start/stop individual programs.
• For example: /etc/resolv.conf, /etc/logrotate.conf

5. /dev – Device Files

• Contains device files.
• These include terminal devices, usb, or any device attached to the system.
• For example: /dev/tty1, /dev/usbmon0

6. /proc – Process Information

• Contains information about system process.
• This is a pseudo filesystem contains information about running process. For example: /proc/{pid} directory contains information about the process with that particular pid.
• This is a virtual filesystem with text information about system resources. For example: /proc/uptime

7. /var – Variable Files

• var stands for variable files.
• Content of the files that are expected to grow can be found under this directory.
• This includes — system log files (/var/log); packages and database files (/var/lib); emails (/var/mail); print queues (/var/spool); lock files (/var/lock); temp files needed across reboots (/var/tmp);

8. /tmp – Temporary Files

• Directory that contains temporary files created by system and users.
• Files under this directory are deleted when system is rebooted.

9. /usr – User Programs

• Contains binaries, libraries, documentation, and source-code for second level programs.
• /usr/bin contains binary files for user programs. If you can’t find a user binary under /bin, look under /usr/bin. For example: at, awk, cc, less, scp
• /usr/sbin contains binary files for system administrators. If you can’t find a system binary under /sbin, look under /usr/sbin. For example: atd, cron, sshd, useradd, userdel
• /usr/lib contains libraries for /usr/bin and /usr/sbin
• /usr/local contains users programs that you install from source. For example, when you install apache from source, it goes under /usr/local/apache2

10. /home – Home Directories

• Home directories for all users to store their personal files.
• For example: /home/john, /home/nikita

11. /boot – Boot Loader Files

• Contains boot loader related files.
• Kernel initrd, vmlinux, grub files are located under /boot
• For example: initrd.img-2.6.32-24-generic, vmlinuz-2.6.32-24-generic

12. /lib – System Libraries

• Contains library files that supports the binaries located under /bin and /sbin
• Library filenames are either ld* or lib*.so.*
• For example: ld-2.11.1.so, libncurses.so.5.7

13. /opt – Optional add-on Applications

• opt stands for optional.
• Contains add-on applications from individual vendors.
• add-on applications should be installed under either /opt/ or /opt/ sub-directory.

14. /mnt – Mount Directory

• Temporary mount directory where sysadmins can mount filesystems.

15. /media – Removable Media Devices

• Temporary mount directory for removable devices.
• For examples, /media/cdrom for CD-ROM; /media/floppy for floppy drives; /media/cdrecorder for CD writer

16. /srv – Service Data

• srv stands for service.
• Contains server specific services related data.
• For example, /srv/cvs contains CVS related data.

 

Types of Files in Linux 

There types for file are there in Linux 

1.Regular file (-)

2. Directory file (d)

3.Special files (there are five types of special files)

1. Block file(b)

2. Character device file(c)

3. Named pipe file or just a pipe file(p)

4. Symbolic link file(l)

5. Socket file(s) 

	Regular or ordinary file start with -
	Directory file start with d
	Link file start with l
	Block special file start with b
	Named pipe file start with p
	Character special file start with c
	Socket file start with s