System Files

Essential system binaries such as ls, cp, and bash.

Essential system binaries for administrative tasks such as fsck and reboot.

Contains most user utilities and applications.

• /usr/bin: user binaries such as Vim and Python.
• /usr/sbin: administrative binaries.
• /usr/lib: libraries used by programs in /usr/bin and /usr/sbin.
• /usr/local: manually compiled or locally installed software.

Self-contained third-party or proprietary software, for example Google Chrome or MATLAB.

System and application configuration files, for example /etc/hosts and /etc/passwd.

Essential shared libraries required by programs in /bin and /sbin.

Variable data such as logs, caches, and changing application files.

• /var/log: system logs such as syslog and auth.log.
• /var/www: web server files.

Home directories for normal users, for example /home/user.

User-specific applications and application data.

• ~/.local/bin: executables installed for one user.
• ~/.local/share: user-specific application data.

A user-created location for personal scripts or programs.

Device files such as /dev/sda for disks and /dev/null.

A virtual filesystem that exposes information about running processes.

A virtual filesystem used for system and hardware information.

Common mount points for filesystems.

• /mnt: temporary mounts.
• /media: removable media such as USB drives.

Boot-related files such as kernels and the GRUB bootloader.

Temporary files. The original note describes these as being cleared on reboot.

Home directory for the root user.

Runtime data such as process IDs and sockets.