🐧 Day 1 · Linux Fundamentals & Filesystem
Before you automate anything, you have to understand the machine you're standing on.
How Linux is actually built - 4 layers:
Hardware → Kernel → Shell → User Programs
The kernel talks to hardware. The shell (Bash) is how you talk to the kernel. Master that conversation and the rest of DevOps opens up.
Distros aren't different operating systems - same kernel, different packaging:
→ Debian family (Ubuntu, Debian) → apt
→ Red Hat family (RHEL, CentOS, Fedora) → yum/dnf
Learn the filesystem map - you'll live in it daily:
/etc = configs ·
/var = logs ·
/home = users ·
/bin = essential commands ·
/proc = live kernel info
And the rule that explains everything: in Linux, everything is a file - even devices and processes.
Your first 4 commands to run right now:
pwd # where am I?
ls -lah # list files (long, all, human sizes)
cd /var/log
whoami # which user am I?
⚠️ One trap to remember:
/ is the root of the tree.
/root is the root user's home. Don't confuse them.
That's Day 1. You now understand the structure.
Tomorrow we move fast through essential commands & navigation.
Save this. Day 2 drops tomorrow. 🚀
Before Docker & Kubernetes, Linux for DevOps 👇👇