---
title: Linux Directories
parent: Cybersecurity Linux
grand_parent: Class Notes
---
# Linux Directories
Cybersecurity Linux Lesson 1.1.1

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## <span style="color:rgb(255, 0, 0)">/boot</span>  (boot)
-  The /boot (read as root, boot) directory contains all the files required for the system's boot process
	- Includes the kernel of the system, RAM images, bootloader configuration files, etc.  
## <span style="color:rgb(255, 0, 0)">/proc</span>   (processes)
- The /proc directory contains information about processes, hardware configuration, and kernel parameters
	- E.g. /proc/in.fo provides information about the system's CPU  
## <span style="color:rgb(255, 0, 0)">/sys</span>    (system info)
- The /sys directory holds information about the kernel parameters and device attributed
    - E.g. /sys/gpio can manipulate the GPIO pins on embedded systems
## <span style="color:rgb(255, 0, 0)">/var</span>    (variables)
- The /var directory contains all the files that change while the system is being used
	- Mainly used for storing variables data that is generated by services and applications
	- Logs are stored in /var/log
	- Cached data is stored in /var/cache  
## <span style="color:rgb(255, 0, 0)">/usr</span>    (user's info)
- The /usr directory contains data and resources about system users
	- /usr/bin contains commands, executables, utilities, and applications
	- /usr/share contains fonts, images, documentations, etc
## <span style="color:rgb(255, 0, 0)">/lib</span>    (libraries)
- The /lib directory contains libraries for the system typically needed for the early stages of the boot process
	- Occassionally split in /lib32 and /lib 64 for 32-bit and 64-bit libraries, respectively  
## <span style="color:rgb(255, 0, 0)">/dev</span>    (hardware devices)
- The /dev directory contains device files that provide access to hardware devices on the system
	- /dev/sda typically represents the first hard drive (or /dev/sda1 as first partition)
	- /dev/ttyS0 is usually a serial port
	- /dev/null and /dev/zero are used for input/output
## <span style="color:rgb(255, 0, 0)">/etc</span>    (config files)
- The /etc directory contains configuration files and shell scripts for the system
	- /etc/fstab is the file system table  
## <span style="color:rgb(255, 0, 0)">/opt </span>   (optional software)
- The /opt directory holds optional/add-on software packages
	- Allows for easy management and helps prevent conflicts with system files  
## <span style="color:rgb(255, 0, 0)">/bin</span>    (binaries or commands)
- The /bin directory contains the essential executable files for the system to function
	- Contains the fundamental commands for the system to function including ls, cp, mv, etc.
## <span style="color:rgb(255, 0, 0)">/sbin </span>  (system binaries or commands)
- The /sbin directory is reserved for system administrators and contained essential system binaries
	- Commands included within this directory are fdisk, reboot, and ifconfig 
	- These commands must be run as superuser
## <span style="color:rgb(255, 0, 0)">/home</span>   (user directory folder)
- The /home directory is where system users home directories are located
	- /home/student would be the home directory for a user, student  
## <span style="color:rgb(255, 0, 0)">/root</span>   (root directory folder)
- The /root directory is the home directory for the superuser/root account
	- Contains config files, scripts, etc.
## <span style="color:rgb(255, 0, 0)">/media</span>  (removable storage devices)
- The /media directory is used as a mount point for removable media devices such as USB drives, external hard drives, optical discs, etc.  
## <span style="color:rgb(255, 0, 0)">/mnt</span>    (mount point)
- The /mnt directory is a general-purpose mount point used for temporarily mounting filesystems or devices
	- /mnt can be used for any kind of mount operation  
## <span style="color:rgb(255, 0, 0)">/tmp</span>    (temporary files)
- The /tmp directory is a location for storing temporary files and directories
	- May be deleted by the system during reboots or to free up disk space