Linux File System Hierarchy for DevOps Engineers

DevOps Zero to Job-Ready – Day 12/180 | Conditionals & Loops in Bash Scripts shouldn’t run blindly — they should react based on conditions. Conditionals (`if`) allow decisions like checking if a file or server exists. Loops (`for`, `while`) help repeat tasks across files, logs, or retries. This is what makes scripts dynamic instead of static commands. More structured DevOps notes and scenarios available on [www.engidock.com] #DevOps #Linux #Automation

🔧 When a Simple Install Turns Into a Kernel-Level Lesson Today I just wanted to install VirtualBox so I could spin up a Linux machine for practicing and working on some DevOps stuff. I thought it would take a few minutes… but it turned into a small troubleshooting journey. At first, VirtualBox wouldn’t start and kept throwing the rc=-1908 error. After digging a bit, I realized I was running kernel 6.17, and the required module (vboxdrv) wasn’t being built properly. Even reinstalling didn’t help because DKMS still failed to build the module on that kernel. The workaround was booting into a more stable kernel (6.14) so the modules could finally build. I thought that would solve everything, but there was one more blocker: Secure Boot. It was preventing the module from loading and kept returning a “Key was rejected” error. After disabling Secure Boot and loading the modules, VirtualBox finally started working. What I expected to be a simple installation ended up being a good reminder: sometimes issues come from different layers of the system, and the only way forward is to debug them step by step. #DevOps #Linux #Troubleshooting #VirtualBox #Kernel #DKMS #LearningJourney

If you're new to DevOps, understanding Linux is essential as it serves as the foundation for everything that runs. Here are the 10 Linux commands that every DevOps engineer uses daily: 1. pwd — where am I? 2. ls -la — what's here? (including hidden files) 3. cd — move around 4. cat / less — read files without opening an editor 5. grep "error" /var/log/app.log — find what matters in logs 6. top / htop — what's consuming my CPU/memory? 7. df -h — how much disk space is available? 8. chmod / chown — resolve permission errors 9. ps aux | grep nginx — is that process running? 10. curl -I https://yourapp.com — test endpoints from the terminal Pro tip: Don't just memorize these commands; use them every day on a real server or a local VM. The muscle memory develops through practice, not just reading. Which Linux command do you use the most? Share it below, and I'll compile the community's top 10. #Linux #DevOps #SysAdmin #Beginners #CloudEngineering

DevOps Zero to Job-Ready – Day 14/180 | Backup Automation Script This is where scripting becomes real. Instead of isolated commands, a script now solves an actual problem — automating backups. Creating archives, naming them with dates, and running without manual effort. No one should remember to take backups — it should just happen. More structured DevOps notes and scenarios available on www.engidock.com. Next: Networking basics (IP & DNS) #DevOps #Linux #Automation

Most people think “maintenance mode” means shutting everything down. But in real-world systems, that’s not how it works. I built a small project to explore how Linux servers actually handle maintenance using systemd (.targets) + Nginx + automation scripts. Instead of killing the server, this setup: Keeps SSH access alive Keeps Nginx running Switches traffic to a maintenance page Uses a custom maintenance.target to control the system state Automates everything through a single script The idea was to understand how targets and services work together in systemd, and how this concept is applied in real DevOps environments. It’s a simple setup (just two HTML pages), but it demonstrates a powerful concept: controlled downtime instead of a total shutdown Project link: https://lnkd.in/e7-SV5T3 Would love to hear feedback or suggestions. #linux #DevOps #systemd

🚀 Linux & DevOps: Practical Field Guide I’ve put together a concise, hands-on reference for developers and junior DevOps engineers - covering the essentials you actually use in real projects. From package management and user setup to LVM, networking, and NGINX - this guide focuses on practical commands, real scenarios, and common pitfalls. 💡 Highlights: - User & group management with real examples - Safe sudo configuration best practices - LVM setup from scratch - Swap, networking, and static routes - NGINX setup + production tips No theory overload - just what you need to get things done. Perfect as a quick cheat sheet when working with Linux in daily tasks. #Linux #DevOps #NGINX #Networking #Backend #SysAdmin #Engineering

Day 7/100 – Setting Up Password-less SSH Authentication in Linux It's Day 7 already. 🎉 Today, I was presented with another real world DevOps challenge; To implement password-less SSH access between a jump host and multiple app servers. The goal was to allow a user (thor) on the jump host to connect to other servers using their respective sudo users without being prompted for a password. This is especially important for scripts that run automatically and need uninterrupted access (like the cron job worked on yesterday). The first thing I did was to generate an SSH key pair using "ssh-keygen -t rsa" and distribute the public key to each app server using "ssh-copy-id". Once that was done, I tested the connections and confirmed that access was successful without any password prompts. Password-less access is essential for cron jobs and scripts. Security is about balance: automation vs controlled access and knowing when each is desired. This is one of those behind-the-scenes setups that makes CI/CD pipelines, remote scripts, and large-scale infrastructure actually work. One day at a time till perfection.🚀 #DevOps #CloudEngineering #Linux #SSH #TechLearning #100DaysOfCode # #SystemAdministration #LearningInPublic

Linux Troubleshooting - Real Production Scenarios. 2 AM. Pager goes off. “Server is down.” No documentation. No hints. Just you, a terminal, and production pressure. Here are real troubleshooting scenarios every DevOps engineer should know #Linux #DevOps #SRE #Troubleshooting #SysAdmin #CloudEngineering #100DaysOfDevOps #InfrastructureAsCode #LinuxAdmin #TechCommunity

🚀 Linux Command Spotlight: touch One of the most useful Linux commands in daily operations is touch. 👉 touch is used to create empty files or update the timestamp of existing files. 💡 Why it matters in DevOps & System Administration: When working on Linux servers, scripts, configuration files, logs, or application setups, creating files quickly is a common task. 🛠 Real-time Example: touch file.txt Creates an empty file named file.txt. touch app.conf script.sh notes.txt Creates multiple files at the same time. touch /opt/app/config.yaml Creates a file in a specific path. touch existingfile.txt Updates the modified timestamp of an existing file. touch -t 202604191200 sample.txt Creates or updates a file with a specific date and time. touch .env Creates a hidden file. ✅ Common Use Cases: • Creating script files • Preparing configuration files • Creating log files • Updating timestamps for automation tasks • Generating hidden environment files • Creating multiple files quickly A simple command that plays an important role in Linux file handling and server operations. #Linux #DevOps #SystemAdministration #CloudComputing #AWS #Infrastructure #TechSkills #Automation #ITOperations #LinuxCommands

🌐 Tech Concept of the Day: Bash 🐚 🐚 Bash (Bourne Again Shell) is a powerful command-line shell and scripting language used to interact with operating systems and automate repetitive tasks in Linux and Unix-based environments. 🔧 Where is Bash commonly used? 🔹 Running system commands (creating files, managing folders, installing software) 🔹 Automating repetitive tasks using shell scripts (.sh files) 🔹 Managing servers and system configurations 🔹 Combining multiple commands into a single workflow 🔹 Scheduling automated jobs using cron 💡 One-Line Tip: Bash = Type commands once → automate tasks forever. 📌 Whether you're a developer, system administrator, or DevOps enthusiast, mastering Bash can significantly boost your productivity and efficiency. #Bash #Linux #DevOps #Automation #ShellScripting #TechConcept #LearningInPublic #DeveloperTools