An Operating System (OS) is system software that manages computer hardware and allows applications to run.
It acts as a bridge between the user and the computer hardware.
Examples: Windows, Linux, macOS, Android.
Kernel and User Space
Kernel: Core part of OS that directly controls hardware (CPU, memory, disk)
User Space: Programs and applications used by users
Why Linux is Important
Linux is the most widely used operating system in servers and cloud computing.
Most websites, applications and cloud platforms run on Linux servers.
Linux Distributions
Ubuntu
CentOS
Red Hat Enterprise Linux
Debian
Basic Terminal Commands
pwd – show current directory
ls – list files
cd – change directory
mkdir – create folder
rm – delete files
Users and Permissions
root user – administrator
chmod – change permissions
chown – change ownership
Processes and Services
Linux runs many processes in the background called services.
These services keep servers and applications running continuously.
Remote Access (SSH)
SSH (Secure Shell) allows you to remotely connect to a server securely using the internet.
It is the primary way engineers manage cloud servers.