Day 5 – Understanding Linux
Shaharyar Shakir
🔍 Why Linux?
Linux is:
Open-source and community-driven
Extremely customizable
Powers most servers, containers (like Docker), and cloud platforms
Essential for DevOps, SysAdmin, and SRE roles
🧠 Linux Principles I Learned
Everything is a file (even devices!)
Permissions and ownership are critical
Users and groups define access control
The terminal is powerful, not scary
Stability and security make Linux ideal for servers
📁 Important Linux Directories
| Directory | Purpose |
/home | User files |
/etc | Configuration files |
/var | Logs, mail, spools |
/usr | User apps and libraries |
/bin | Essential binaries |
/sbin | System binaries |
/opt | Optional software |
/boot | Bootloader files |
🧪 RPM vs DEB – Two Package Worlds
| Type | Description | Used By |
| RPM | Red Hat Package Manager | RHEL, CentOS, Fedora |
| DEB | Debian Package | Debian, Ubuntu, Mint |
Each has its own tools:
rpm,yum,dnf(for RPM)dpkg,apt(for DEB)
🧬 Popular Linux Distros
| Distro | Based On | Use Case |
| Ubuntu | Debian | Beginner-friendly, servers, cloud |
| Debian | – | Stable, minimal |
| CentOS | RHEL | Enterprise servers (now replaced by CentOS Stream) |
| Fedora | RHEL | Cutting-edge |
| Arch | – | Rolling release, minimal, advanced users |
| Alpine | – | Tiny, used in containers |
🌐 Linux in Servers
Nearly all cloud VMs (AWS, Azure, etc.) run Linux
Server distros focus on stability, CLI tools, and remote management
You’ll often SSH into Linux servers, not use a GUI
📌 Summary
Today helped me build a strong mental model of Linux. I understand why it's used everywhere in DevOps, and the difference between distros and packages.
Tomorrow, I’ll get hands-on with basic terminal commands and file operations.
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