BitVistara

Linux Directory Architecture

Filesystem Hierarchy Standard (FHS) overview

Linux follows the Filesystem Hierarchy Standard (FHS), which defines the structure and purpose of directories. This standardization ensures consistency across distributions and helps both users and developers understand where files belong. Every directory has a specific purpose, from storing essential system binaries to user data and configuration files.

/ (root filesystem)

├── /bin Essential binaries

├── /boot Boot files, kernel

├── /dev Device files

├── /etc Configuration files

├── /home User home directories

├── /lib Shared libraries

├── /media Removable media

├── /mnt Mount points

├── /opt Optional software

├── /proc Process info (virtual)

├── /root Root user home

├── /run Runtime data

├── /sbin System binaries

├── /srv Service data

├── /sys System info (virtual)

├── /tmp Temporary files

├── /usr User programs

└── /var Variable data

Understanding this structure is crucial for system administration. For example, system binaries are typically in /bin or /usr/bin, while configuration files that control system behavior are located in /etc. User files and applications often reside in /home, while log files and other variable data are stored in /var.

Key Directories

/etc — System-wide config
/var/log — Log files
/usr/bin — User binaries
/opt — Third-party software
/tmp — Temporary (cleared on reboot)

Virtual Filesystems

/proc — Process & kernel info
/sys — Hardware & drivers
/dev — Device nodes
/run — Runtime state

Some directories like /proc and /sys are virtual filesystems that don't actually exist on disk. They provide interfaces to kernel and system information, allowing you to interact with the system through filesystem-like operations. It's important to follow FHS conventions to maintain system stability and ensure compatibility across different Linux distributions.

Best Practices

Never write to / or /usr directly
User data goes in /home or /var
Configs belong in /etc
Logs should be in /var/log