Troubleshooting Linux Command Not Found Error

🚨 Why your service is not starting in Linux? (Quick troubleshooting) You try to start a service… But it fails 😓 This is very common in real-world scenarios. Instead of guessing, follow this simple approach 👇 --- 🔍 1. Check service status `systemctl status nginx` 👉 Shows error messages 👉 Gives first clue about the issue --- 📄 2. Check logs `journalctl -u nginx` 👉 Detailed logs of the service 👉 Helps identify exact problem --- ⚙️ 3. Check configuration 👉 Wrong config is a very common reason Example: `nginx -t` 👉 Validates config before restart --- 🔌 4. Check port usage `ss -tuln | grep 80` 👉 Maybe port already in use --- 🔐 5. Check permissions 👉 Service may not have required permissions 👉 File or directory access issue --- 🧠 Real mindset: Don’t restart again and again ❌ Read the error and fix root cause ✅ --- 💡 Final thought: In Linux, errors always tell you the story. You just need to read them carefully 🚀 #Linux #LinuxAdmin #DevOps #Troubleshooting #CloudComputing #SystemAdministration #LearningInPublic #ITInfrastructure

A small Linux lesson I revisited recently: the difference between .bashrc and .bash_profile. At first glance they seem similar, but they serve different purposes. 1. .bash_profile is typically loaded when you start a login session Examples: signing into a Linux machine through SSH, logging in on a TTY, or starting a fresh user session. 2. .bashrc is usually loaded for interactive shell sessions Examples: opening a new terminal window, launching another Bash shell from an existing terminal, or starting a new shell tab. That small distinction explains why aliases, environment variables, or PATH changes sometimes work in one session but not another. A common industry practice is to keep session-level environment variables in .bash_profile, shell customizations in .bashrc, and then source .bashrc from .bash_profile so login sessions inherit the same aliases, functions, and prompt settings. It’s a simple pattern, but it keeps environments consistent across local machines, remote servers, and development containers. #LFS #Linux

Linus Torvalds releases Linux Kernel 7.0 RC 7, the final candidate before the official 7.0 launch. Learn what's new in Linux 7.0-rc7. Full release note here: https://lnkd.in/gVecZnPt #Kernel70 #Linux #RC7 #Opensource #Releases

Had a situation where a VM wasn’t responding… At first glance, it looked like: Application issue But digging deeper: •CPU was fine •Memory was fine •Network looked stable Then checked disk… 👉 100% full. That was it. Sometimes the simplest things hide behind complex symptoms. Always check the basics even when it feels “too obvious”. #DevOps #Linux #RealWorld #Troubleshooting

🚨 “Too many open files” error in Linux? Here’s what it means Application suddenly stops or throws error 😓 And logs show: “Too many open files” This can be confusing at first. Let’s simplify it 👇 --- 🧠 What does it mean? Every process in Linux has a limit on how many files it can open. 👉 Files = logs, sockets, connections, etc. If limit exceeds → error appears 🚨 --- 🔍 1. Check current limits `ulimit -n` 👉 Shows max open files allowed --- 📊 2. Check usage `lsof | wc -l` 👉 Total open files in system --- 🧾 3. Check per process `lsof -p <PID>` 👉 Which process is opening too many files --- ⚙️ 4. Temporary fix `ulimit -n 65535` 👉 Increase limit for current session --- 🔐 5. Permanent fix Edit: `/etc/security/limits.conf` 👉 Increase limits for user/process --- 🧠 Common reasons: * High traffic * Too many connections * Application not closing files properly * Log file overload --- 💡 Final thought: System limits are silent… Until they break your application 🚀 Always keep an eye on them. --- #Linux #LinuxAdmin #DevOps #Troubleshooting #CloudComputing #SystemAdministration #LearningInPublic #ITInfrastructure

🐧 File Permissions vs Ownership (Why Access Fails in Linux) “Permission denied” is one of the most common Linux errors. But it usually comes down to two things 👇 🔐 1. Permissions Define what actions are allowed: • Read (r) • Write (w) • Execute (x) Applied to: • User • Group • Others 👤 2. Ownership Every file has: • Owner (user) • Group ⚙️ Key Commands "ls -l" → View permissions & ownership "chmod" → Change permissions "chown" → Change owner 🚨 Common Scenarios • Script not running → missing execute permission • App can’t access file → wrong owner • Service fails → incorrect group permissions 🧠 Real Insight Permissions control what can be done Ownership controls who can do it 💡 Key Insight Most access issues are not complex — they’re just permissions and ownership. #Linux #DevOps #SystemAdmin #Security #CloudEngineer #LinuxCommands

Before troubleshooting any Linux system, I run these commands. An 8-step Linux triage checklist with exact flags and what to do when you find a problem. Read full guide here: https://lnkd.in/gvhsycY6 #Linuxtroubleshooting #Linuxadmin #Linuxhowto #Linuxcommands

Day 12/100 — Linux Network Services 🔧🌐 Apache wasn't reachable on port 3003. Turns out sendmail was occupying the port, blocking Apache from starting. Fixed the conflict, then tackled a second issue — iptables was blocking external access even after Apache was running. 🔑 Key Takeaway: "Service is running" and "service is reachable" are two different things. Always check both the application layer AND the network layer when troubleshooting connectivity issues. Day 12 ✅ | 88 more to go! #DevOps #Linux #Networking #Apache #Troubleshooting #KodeKloud #100DaysOfDevOps #LearningInPublic

🚀 5 simple Linux commands that can save your time during troubleshooting When working on a Linux server, sometimes you don’t need complex tools. A few simple commands can quickly tell you what’s wrong. Here are 5 commands I often rely on 👇 🔍 `grep` Used to search specific text inside files. Very useful when checking logs. Example: `grep error /var/log/syslog` --- 📜 `tail -f` Shows logs in real time. Example: `tail -f /var/log/syslog` Perfect for monitoring live activity. --- 🔎 `find` Helps locate files based on name, size, or type. Example: `find / -name file.txt` --- 📦 `du -sh` Shows size of directories. Example: `du -sh *` Useful when checking which folder is consuming space. --- ⚡ `history` Shows previously used commands. Helps repeat or debug past actions. --- 💡 Key takeaway: You don’t always need advanced tools. Knowing how to use basic commands effectively can save a lot of time during real issues. Small tools, big impact. 🚀 #Linux #LinuxAdmin #DevOps #CloudComputing #SystemAdministration #LearningInPublic #ITInfrastructure

💾 Linux Tip: Find what’s eating your disk space Ever logged into a server and seen: 👉 “Disk almost full”… but no idea why? Here’s a simple command that shows the biggest files and folders: du -ah / | sort -hr | head -20 💡 What it does: • du -a → lists all files and directories with size • sort -nr → sorts from largest to smallest • head -20 → shows top 20 results 🧠 Why this matters: This helps you quickly: • find huge log files • detect storage issues • clean up space before something breaks ⚡ Real scenario: Logs or backups can silently grow and crash your server. This command helps you catch it early. #linux #sysadmin #it #networking #learning