Functional Structure

Linux operating system is structured in a tree-like form and follows the Filesystem Hierarchy Standard (FHS). The main file system folders that compose the structure can be represented in the following diagram:

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Common Directories

Some common directories in a Linux filesystem that play key roles in system configuration, file storage, operational functions, and performance are:

• /: Root filesystem where all of the files required to boot Linux are stored

• /etc: Store configuration files that are used by the operating system

  • /etc/bash.bashrc: Script that contains bash settings

  • /etc/passwd: List of all user accounts

  • /etc/issue: Usually contains information about the OS

  • /etc/crontab: Contains the cronjobs that are executed by the system

  • /etc/shadow: Contains encrypted information about credentials

• /var: Store data that is frequently accessed or written by services or applications running on the system

  • /var/www/html: Default store for the server root folder

• /root: Home directory of the root system user

• /tmp: Temporary files, store data that is only needed to be accessed once or twice, once the computer is restarted, the content of this folder is cleared out

• /opt: Stands for optional, normally third-party software information

• /bin: Basic programs of Unix (binaries)

• /sbin: Binary programs for system administration

• /usr: Contain users' information

  • /usr/bin: Installed packages and applications

  • /usr/share: Application support and data files

• /proc: Contains information about internal jobs and processes of the system

  • /proc/version: Information about OS

• /media: Where external devices are mounted