[Linux][System] Learning Linux File Structure

Check out the reference yt video for more infos
2022.03.26

/bin

• System Binaries (programs, applications)
• Must be accessable in single user mode (check out linux runlevels or wiki)
• UNIX system resource
• installing a user program is not placed in this folder

/bin/cat
/bin/ls
/bin/bash
/bin/chmod 

/sbin

• System Binaries for system administrator (programs, applications)
• Must be accessable in single user mode (check out linux runlevels or wiki)
• UNIX system resource
• installing a user program is not placed in this folder

/boot

• Contains Boot loaders
• Everything OS needs when boot

/dev

• Devices
• Architecture following UNIX (Everything is a file)
• Where application and drivers will access for devices(webcam, keyboard etc)

# Example
# Hardware disk
/dev/sda
# Disk partition
/dev/sda1

/etc

• Etcetera
• System-wide Configurations
• System-wide application settings

/etc/apt
/etc/apt/sources.list

/lib, /lin32, /lib64

• library
• files that applications can use
• used by bin | sbin

/media

• mount drives
• USB disck, external hard drive, second hard drive (B Drive, D Drive)
• manage by OS

/media/<username>/<device-name>

/mnt

• mount drives
• manage manually

/opt

• Optional folder
• Software from vendors, example: Virtual box guest addition
• Also a place to install sofware you create yourself

/opt/<software-folder>/<software-stuffs>

/proc

• Processes
• Pseudo file of Informations and resources for every process
• Like /dev, but not acually file but some information generate by kernal
• Handy information for System status, provide by kernal

/proc/<PID>/<file-for-that-process>
/proc/cpuinfo
/proc/uptime

/root

• Home folder for root users
• need root permission to access

/run

• tempfs file system
• file system which runs in RAM, will disappear when reboot or shutdown

/snap

• Snap package were stored here (check out snap packages)
• mainlly used by Ubuntu

/snap/bin/
/snap/gnome-3-26-1604/

/srv

• service data
• FTP server or web server will store files here for external user to access
• Can mount this folder from another hard drive

/sys

• System folder
• Interact with kernel
• Similar to /run (not physically written to disk), created every time the system boots up.

/sys/dev/
/sys/kernel/
/sys/devices/
/sys/bus/

/tmp

• temporary directory
• application could store some auto save file here to prevend application crashes

/usr

• Universal System Resource
• Non-essential applications for basic system operation

/usr/bin/
/usr/sbin/
/usr/lib/
/usr/local/bin/
/usr/local/sbin/
/usr/local/lib/
/usr/share

/var

• Variable directory
• Contains files and directories that are expected to grow in size

/var/crash/
/var/log/

/home

• Home folder for eash user
• Can mount this folder from different drive, so user can reinstall system and preserve your file
• Hidden directory here to store your application setting

/home/<username>/Desktop
/home/<username>/.cache
/home/<username>/Documents

/cdrom

• legacy mounting point for CD-Rom

Other Information

Q1: How to access to / folder

• Open terminal and use command cd /
• Open Files GUI, select +Other Location and select your system drive

Reference

• https://www.youtube.com/watch?v=HbgzrKJvDRw