``Most beginners say:
“I’m learning Linux.”
But today I realized something important:
Linux is not Ubuntu.
Linux is not the terminal.
Linux is not the full OS.
Linux is the Kernel.
And understanding that changes everything.
🧩 What Linux Actually Is
Linux = Kernel.
The Kernel:
Manages CPU scheduling
Allocates memory
Controls filesystems
Manages processes
Enforces permissions
Handles networking
Everything else runs on top of it.
Without the kernel, the system doesn’t function.
🏗️ The Core Architecture
User → Shell → Kernel → Hardware
This simple model explains:
Permission denied errors
Segmentation faults
Memory exhaustion
High CPU usage
Zombie processes
Every issue traces back somewhere in this chain.
🔎 Kernel Version Commands
uname -a
uname -r
rpm -q kernel
Why it matters:
Two RHEL servers can have different kernel versions because: Kernels update independently
Systems may not have rebooted
Version locks may exist
Multiple kernels can coexist
This is production-level awareness.
🔄 Bootloader & Default Kernel
grubby --default-kernel
grubby --info=ALL
grubby --default-index
Even if you install a new kernel, it won’t run unless it’s the default boot entry.
This is why updates sometimes “don’t apply.”
🐚 What the Shell Does
The shell (like bash) is a command interpreter.
When you type: ls
The shell asks the kernel to create a process.
The kernel interacts with hardware.
The result comes back to you.
You never directly control hardware.
🚀 Why DevOps Requires Linux Fundamentals
DevOps is about:
- Automation
- Production reliability
- Troubleshooting Most infrastructure runs on Linux.
If you don’t understand:
- Process management
- Networking
- Filesystems
- Kernel behavior
You can’t properly debug real-world systems.
📚 I’ve documented the full breakdown with visuals and explanations in my GitHub repo:
👉 [https://github.com/CloudDevOpsHarsh/linux-foundation-learning/tree/f335e10c7b2399a611d6185188b04ffe937e102d/01-introduction-to-cli]
❓ Your Turn
What concept in Linux clicked late for you but changed everything once it did?
Top comments (2)
That's Impressive !
thanks mate.....:)