Linux Init and Run Levels

Init (initialization) program is used to start the essential processes in the system.

Linux has 7 run levels ran by the INIT:

• Level 0: Shut down the system
• Level 1: Rescue boot to solve problems
• Level 2: Not important for current context
• Level 3: Used when Linux is used as a server
• Level 4: Not important for current context
• Level 5: Normal boot like level 3 but with a GUI
• Level 6: Reboot the system

Important Linux Directories

Commands that can be written in the terminal are stored in two directories:

• bin: Commands for all tools and custom tools
• sbin: System commands
• etc: Saves configurations of the system
• home: Contains user directories with their files
• boot: Has booting information for system start like the 7 levels
• lib (libraries): Has helping libraries for commands
• var: Contains all system logs
• usr: Has tools and commands installed for specific users