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DevOps Roadmap — Part 3: Linux Users, Processes & System Control

DevOps engineers do not work as “admin always”. They work with **users, permissions, and controlled access**.

Understanding users and processes is what separates a beginner from a production engineer.

Linux Users — Why They Exist

Linux is a multi-user operating system. That means:

• Many people can use the same server
• Each user has limited permissions
• Security depends on user separation

DevOps engineers NEVER run everything as root.

Check Current User

whoami

This command tells which user is currently logged in.

Important System Users

• root → superuser (full control)
• ubuntu / ec2-user → cloud default users
• service users → apps like nginx, mysql

Running applications as root is dangerous.

Switching Users Safely

sudo su

sudo apt update

sudo is the heart of DevOps safety.

Linux Processes — Programs in Action

Every running program is a process.

Web servers, databases, containers — everything runs as processes.

ps aux

top

If a server is slow, process analysis is the first step.

Killing a Process (Carefully)

kill 1234

kill -9 1234

Wrong kill command can crash production. Always double-check.

System Services (Background Programs)

Linux servers run services like:

• nginx
• docker
• ssh

systemctl status ssh

sudo systemctl start nginx

sudo systemctl enable nginx

Why This Matters for DevOps

CI/CD pipelines, containers, and cloud services all rely on:

• Correct users
• Healthy processes
• Stable services

If you skip this knowledge, DevOps becomes copy-paste chaos.

Next Step in Roadmap

Now that you understand Linux control, we move into networking — how servers talk to the world.