Linux Overview and Layers
Linux
Linux is an open-source operating system based on Unix. It manages hardware resources and provides services for applications.
It is widely used in: – Servers – Cloud environments – Embedded systems – Desktop systems
Layers of Linux Architecture
Linux architecture consists of the following layers:
1.Hardware Layer
Includes physical components: – CPU – Memory (RAM) – Disk – Input/Output devices
2. Kernel Layer
The Kernel is the core of Linux and directly interacts with hardware.
Key responsibilities: – Process management\
- Memory management\
- Device drivers\
- File system management
3. Shell Layer
The Shell acts as an interface between the user and the kernel.
Examples: – bash – sh – zsh
4. Application Layer
Includes user-level applications such as: – Web browsers – Text editors – System tools
Basic Linux Commands with Examples
1. ls (List files and directories)
ls
ls -l
ls -a
2. mkdir (Create directory)
mkdir test_folder
mkdir -p parent/child
3. touch (Create file)
touch file1.txt
touch file2.txt
4. cd (Change directory)
cd test_folder
cd ..
cd /
5. echo (Print / Write data)
Print message
echo "Hello Linux"
Overwrite file
echo "Hello World" > file.txt
Append to file
echo "New line added" >> file.txt
Practice Example
mkdir demo
cd demo
touch file.txt
echo "First line" > file.txt
echo "Second line" >> file.txt
ls
cat file.txt
