Linux Boot Sequence: 8 Hidden Steps to Troubleshoot Like a Pro

Most Linux beginners think "Power On" to "Login Screen" is a single jump, but there is a hidden 8-step sequence happening in the background. During my 2 years managing production servers, I realized that 90% of "unfixable" boot errors are actually easy to solve once you visualize this specific flow. * The BIOS/UEFI runs a hardware check (POST) before handing the baton to your boot loader. * GRUB acts as the brain, reading your config files and loading the kernel into memory. * Systemd kicks in as the "Parent Process" to launch your targets and startup scripts. Mastering this sequence is a proven way to stop guessing and start troubleshooting like a pro. 🐧 Which of these 8 steps usually causes the most headaches in your environment? Follow for more and let's grow together Anis Salhi ________ #Linux #DevOps #SysAdmin #TechTips #Engineering

⚡ Top Linux Mistakes That Slow Down Engineers Linux is powerful — but small mistakes can waste a lot of time. Here are common mistakes engineers make 👇 ❌ Using "rm -rf" without checking Can delete important files instantly ❌ Running commands without understanding Leads to unexpected system issues ❌ Not checking logs Logs often contain the exact problem ❌ Ignoring permissions Permission issues break scripts and services ❌ Not using tab completion Slows down navigation and increases errors ❌ Repeating commands manually Instead of using history or scripts ✔ Better Approach • Verify before executing critical commands • Read logs ("journalctl", "/var/log") • Use "history" and shortcuts • Automate repetitive tasks • Understand permissions ("chmod", "chown") 💡 Key Insight Linux is fast — but only if you use it smartly. #Linux #DevOps #SystemAdmin #CloudEngineer #LinuxTips #Productivity #SRE

🐧 Disk Usage Debugging in Linux (Find What’s Eating Space Fast) “Disk full” is one of the most common production issues. Here’s how engineers quickly find the problem 👇 💾 1. Check Overall Disk Usage "df -h" See which partition is full 📂 2. Find Large Directories "du -sh /* | sort -rh | head" Identify top space-consuming folders 📁 3. Drill Down Further "du -sh /var/* | sort -rh | head" Narrow down to exact location 📜 4. Check Logs "/var/log" often grows fast Clean old logs if needed 🗑️ 5. Clean Unused Files • Remove temp files ("/tmp") • Clear cache • Delete unused backups 🔍 6. Check Deleted but Open Files "lsof +L1" Find files deleted but still used by processes 💡 Key Insight Disk issues are not random — they leave clear traces if you check step by step. #Linux #DevOps #SystemAdmin #Troubleshooting #CloudEngineer #LinuxCommands #SRE

Most people learn Linux by watching tutorials… But in production, you don’t get tutorials—you get problems. Here are some Linux commands that actually saved me in real situations 👇 Must-Know Linux Commands:- ls – See what’s in a directory cd – Move between folders pwd – Know where you are (Simple… but you’ll use them every day) Debugging & Monitoring top / htop – Check CPU & memory usage ps aux – See running processes kill -9 <pid> – Stop a stuck process Logs = Truth cat file.log – View logs less file.log – Read logs easily tail -f file.log – Watch logs live (very useful in production) System Checks df -h – Disk space free -m – Memory usage uptime – System load Networking Basics ping – Check connectivity curl – Test APIs netstat -tulnp – Check open ports You don’t need 100 commands. You need the right 15–20 commands you can use under pressure. 🚀 The day you start reading logs instead of guessing… That’s when Linux starts making sense. #Linux #DevOps #SysAdmin #TechSkills #learnandgrow #dailyblog

Linux From Scratch has been called impractical for years. Fine. Of course it is. It takes at least forty hours, and that is assuming things go reasonably well. When you finish, there is no package manager waiting to rescue you. No clean update path. No layer of polish smoothing over the hard parts. Every binary on that machine exists because you compiled it. Every configuration file exists because you wrote it. That much is obvious. The real question is whether that matters. It does. More than most people are willing to say out loud. Not because LFS belongs on a production server. It does not. Not because it is the smartest way to run a modern environment. It is not. That misses the point completely. The point is what it does to your understanding. Because there is a kind of knowledge that only comes from doing something the hard way, from first principles, with your own hands. You do not get that from browsing a wiki. You do not get it from skimming documentation and nodding along. You get it by getting stuck. By getting it wrong. By sitting in a chroot at two in the morning, staring at a kernel that refuses to compile, and staying there until the system finally makes sense. That experience does something documentation alone cannot do. It burns the lesson in. It forces the abstractions to fall away. It turns Linux from a product you use into a system you actually understand. And once you have that, you keep it. Read more here: https://lnkd.in/gtiUeRhb #Linux #LinuxFromScratch #OpenSource #SystemsEngineering #DevOps #Infrastructure #SoftwareEngineering #OperatingSystems #LearnByDoing #LFS

I think this is the future of recruiting and Jr employee training in the age of AI. It takes a long time and hard work to learn and gain experience. But now, AI means that anyone can take the shortcut. The problem is that the real value (experience) is lost. This is something we will need to replace. Programs like this will start to be an important part of any new employee training program - a way to quickly, but clearly, get some deep and practical experience that advances the person years ahead. The output is not the goal - that will be discarded. The goal is the experience and knowledge that the human gains. This is a very different way to think, and a different way to value human growth. We need to invest in training people and growing them in their ability to do the things that AI can't do. That takes time, but the results are necessary.

🚨 Memory usage high in Linux? Here’s how I troubleshoot it System slow… applications hanging… Most of the time, memory is the reason 😓 Here’s a simple way to check and fix it 👇 --- 🔍 1. Check memory usage `free -h` 👉 Look at: * Used memory * Free memory * Swap usage --- 📊 2. Find top memory consuming processes `ps -eo pid,ppid,cmd,%mem,%cpu --sort=-%mem | head` 👉 Shows which process is using most RAM --- 🧠 3. Use top for live view `top` 👉 Press `M` to sort by memory usage --- ⚠️ 4. Check swap usage 👉 High swap = memory pressure 👉 System becomes slow --- 📄 5. Check for memory leaks 👉 Application consuming more memory over time 👉 Restart may temporarily fix --- 🔄 6. Temporary fix `kill -9 <PID>` 👉 Stop high memory process (carefully) --- 💡 Common reasons: * Memory leak in application * Too many processes * High traffic * Insufficient RAM --- 💡 Final thought: High memory is not the problem ❌ Not understanding it is the problem ✅ Observe → Analyze → Fix 🚀 #Linux #LinuxAdmin #DevOps #Troubleshooting #CloudComputing #SystemAdministration #LearningInPublic #ITInfrastructure

Day 8 🚀 Today I explored file searching, text processing, and permission management in Linux — essential concepts for working efficiently in real-world server environments. 🔍 Grep (Global Regular Expression Print): Used to search for specific words or patterns inside files. I practiced different options like showing line numbers, counting occurrences, and performing case-insensitive searches. 🔐 Permission commands: Learned how to manage file ownership and access using commands like chown, chgrp, and chmod, including applying changes recursively to directories. 📁 Search commands: Explored how to locate files using: • find – Searches in real-time based on path and conditions • locate – Faster search using a prebuilt database Also understood the key difference between find and locate, and when to use each. This session helped me understand how to control access and efficiently search for files in Linux systems. Step by step, building strong system-level skills. Sharing a quick cheat sheet of the commands I practiced 👇 #DevSecOps #Linux #Grep #Permissions #DevOps #CloudComputing #HandsOnLearning #LearningInPublic #TechJourney

💾 Understanding LVM in Linux (PV, VG, LV) — with a simple example If you’ve ever struggled with disk management in Linux, learning LVM (Logical Volume Manager) is a game changer. 👉 Let’s break it down: 🔹 PV (Physical Volume) This is your actual disk or partition. Example: /dev/sda1, /dev/sdb1 🔹 VG (Volume Group) Think of this as a pool of storage created by combining multiple PVs. Example: Combine /dev/sda1 + /dev/sdb1 → vg_data 🔹 LV (Logical Volume) This is the usable partition created from the VG (like a flexible partition). Example: lv_data created inside vg_data 🧠 How it works together: PV → VG → LV → Filesystem 🚀 Real Example (Commands): 1️⃣ Create Physical Volumes pvcreate /dev/sda1 /dev/sdb1 2️⃣ Create Volume Group vgcreate vg_data /dev/sda1 /dev/sdb1 3️⃣ Create Logical Volume (10GB) lvcreate -L 10G -n lv_data vg_data 4️⃣ Format and Mount mkfs.ext4 /dev/vg_data/lv_data mount /dev/vg_data/lv_data /mnt/data 🔥 Why LVM is powerful: ✔ Resize storage without downtime ✔ Combine multiple disks easily ✔ Take snapshots ✔ Flexible and scalable 💡 Example Use Case: You start with 10GB, later need 20GB → just extend LV without touching data! #Linux #DevOps #LVM #SystemAdministration #CloudComputing #TechLearning #OpenSource #Backend #Infrastructure