Make Linux Interesting: Linux File System Hierarchy Structure

Linux File System Hierarchy Structure

The Linux File System Hierarchy Structure or the Filesystem Hierarchy Standard (FHS) defines the directory structure and directory contents in Unix-like operating systems. It is maintained by the Linux Foundation.

In the FHS, all files and directories appear under the root directory / (ROOT).
Most of these directories exist in all UNIX operating systems;

1. / (Root): Root directory of the entire file system hierarchy

Every single file and directory starts from the root directory which is /.
By default only root user has the right to write under this directory.
Make sure don't confuse with / (ROOT) and root user / mean root file
system and root user means /root .

2. /bin : Essential command binaries that need to be available in single-user mode; for all users, e.g., cat, ls, cp.

Contains binary executables only
All commands store in this directory which you need to use in single-user modes are located under this directory.

3. /boot : Store Boot loader files, e.g., kernels, initrd.

Kernel initrd, vmlinux, grub files are stored under /boot

4. /dev : Store essential device files, e.g., /dev/null.

These include terminal devices, usb, or any device attached to the system.

5. /etc : Store all configuration files.

Contains configuration files required by all programs.
Example: /etc/resolv.conf, /etc/httpd/conf/httpd.conf .

6. /home : Store Users’ home directories, containing saved files, personal settings, etc.

Home directories for all users to store their personal files.
example: /home/nirmal, /home/nks

7. /lib : Libraries essential for the binaries in /bin/ and /sbin/.

Library filenames are either ld* or lib*.so.*

8. /media : Mount points for removable media such as CD-ROMs and others.

Temporary mount directory for removable devices.
Examples, /media/cdrom for CD-ROM; /media/floppy for floppy drives; /media/cdrecorder for CD writer
Note : I'm using Centos 7 so it's showing /run/media , in ubuntu you will see /media/username etc.

9. /mnt : Temporarily mounted filesystems.

Temporary mount directory where sysadmins can mount filesystems.
By default this is blank directory you can mount any filesystem under this

10. /opt : Optional application software packages.

Contains add-on applications from individual vendors like bitnami.
like Xampp or any other software .

11. /sbin : Essential system binaries, e.g., fsck, init, route.

Just like /bin, /sbin also store binary executables.
The linux commands located under this directory are used typically by system administrator, for system maintenance purpose.
Example: iptables, reboot, fdisk, ifconfig, swapon etc

12. /srv : Site-specific data served by this system, such as data and scripts for web servers, data offered by FTP servers, and repositories for version control systems.

13. /tmp : Directory that store temporary files created by system and users.

Files under this directory are deleted when system is rebooted.

14. /usr : Store Secondary hierarchy for read-only user data; contains the majority of (multi-)user utilities and applications.

Contains binaries, libraries, documentation, and source-code for second level programs.
/usr/bin store 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 store 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 store libraries for /usr/bin and /usr/sbin
/usr/local store users programs that you install from source.
/usr/src holds the Linux kernel sources, header-files and documentation.