1. 🐧 Linux Fundamentals for DevOps Engineers
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Open to Work | Cloud & DevOps Engineer | AWS | Kubernetes | Terraform | CI/CD | Automations | Available for Full-Time / Freelance / Mentorship
🔹 Why Linux is Important for DevOps?
Linux is the backbone of:
Cloud servers
Containers
CI/CD runners
Kubernetes nodes
🔹 Process vs Thread
Process: Independent execution unit with its own memory
Thread: Lightweight execution unit sharing process memory
👉 Example: One Java process running multiple threads.
🔹 Check CPU, Memory & Disk Usage
top
htop
free -m
df -h
🔹 Find High Memory Consuming Process
ps aux --sort=-%mem | head
🔹 System Monitoring Commands Explained
| Command | Use |
| top | Real-time stats |
| vmstat | CPU, memory & IO |
| free | RAM usage |
| df | Disk usage |
🔹 Check and Kill a Process
ps -ef | grep java
kill -9 <PID>
🔹 Find Which Service Uses a Port
netstat -tulnp | grep 8080
ss -tulnp
lsof -i :8080
🔹 Linux File Permissions
chmod 755 script.sh
chown user:group script.sh
- r=4, w=2, x=1
🔹 Linux Logs
tail -f /var/log/syslog
journalctl -u docker
journalctl -xe
🔹 Soft Link vs Hard Link
ln -s file softlink
ln file hardlink
| Soft | Hard |
| Cross FS | Same FS |
| Breaks | Safe |
🔹 Troubleshooting Tips
High CPU →
top,htopLow Disk →
du -sh,df -h
🔹 Uptime & Reboot History
uptime
last reboot
🔹 Scheduling Jobs
crontab -e
0 2 * * * backup.sh
🔹 find, grep, awk, sed
find /var -name "*.log"
grep ERROR app.log
awk '{print $1}' file.txt
sed 's/dev/prod/g' file.txt
🎯 Key Takeaways
Linux is non-negotiable for DevOps
Monitoring & troubleshooting are daily tasks
These commands are interview favorites