Linux System Administration & Automation

This part of my DevOps journey was about understanding how a Linux system actually works when you manage it.

Not just running commands ,but knowing what’s happening behind the scenes.

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TL;DR

• Linux basics and user management were easy

• File permissions were confusing at first, then simple

• Log analysis with grep, awk, sed was fun and useful

• Process monitoring was straightforward

• Disk mounts were interesting

• Shell scripting + backup automation was the hardest but most useful

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Why I focused on Linux basics

Before moving to big tools like Docker or CI/CD, I wanted to be clear about:

• who can access the system

• what processes are running

• where data is stored

• how repeated tasks can be automated

If these basics are weak, everything else breaks easily.

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What felt easy

User & Group Management

• Creating users and groups

• Giving sudo access

• Understanding file ownership

Once the idea was clear, the commands made sense.

Process Management

• Running background processes

• Checking them using ps, top, htop

• Killing processes safely

This felt logical and predictable.

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What confused me at first

File & Directory Permissions

At the beginning:

• permissions looked messy

• too many symbols and numbers

What helped:

• thinking in 4-2-1 rule

  • read (4)

  • write (2)

  • execute (1)

After that, setting permissions became easy and clear.

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What I enjoyed learning

Log Analysis (grep, awk, sed)

Working with a real log file taught me how to:

• search useful lines

• extract important fields

• hide sensitive data like IP addresses

• find common log messages

This felt like real DevOps work, not just practice.

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What I found interesting

Volume Management & Disk Usage

Mounting storage and checking it with df and mount helped me understand:

• where data lives

• how storage is attached

• why backups depend on correct mounts

It made Linux storage feel real.

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What was the hardest (but best)

Shell Scripting & Backup Automation

This part took the most thinking.

Writing a script that:

• creates backups with timestamps

• handles errors

• runs automatically using cron

forced me to think in steps and logic, not just commands.

This is where Linux started feeling like automation, not manual work.

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What I learned overall

• Linux is not scary once you understand the basics

• Most confusion comes from missing concepts, not commands

• Logs, permissions, processes, and storage are used daily in DevOps

• Automation feels hard at first and that’s normal

Still learning, still improving.

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GitHub (Practice & Tasks)

All hands-on work is here:
👉 https://github.com/Harish1685/90DaysOfDevOps

If you’re learning Linux,
what confused you the most when you started?

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