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Advanced Linux Commands Every DevOps Engineer Must Know

#linux #devops #cloudcomputing #linuxcommands

Linux is the backbone of DevOps. Mastering advanced Linux commands can significantly boost your productivity and troubleshooting skills. This guide covers essential system monitoring, networking, security, automation, and DevOps-specific commands.

📌 Table of Contents

  1. System and Resource Monitoring
  2. Networking and Connectivity
  3. Process and Job Management
  4. Security and User Management
  5. Disk Management and File Operations
  6. DevOps-Specific Commands
  7. Automation and Scheduling

⚙️ 1. System and Resource Monitoring

Monitor system performance and resource usage with these commands:

htop
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  • A more interactive version of top, displaying system resource usage in real-time. 
vmstat 1 5
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  • Displays CPU, memory, and I/O statistics every second for five iterations. 
iostat -c 2 5
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  • Monitors CPU usage every two seconds, repeated five times. 
sar -u 5 5
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  • Collects and reports CPU usage statistics every five seconds. 
mpstat -P ALL 5
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  • Displays per-core CPU usage every five seconds.

🌐 2. Networking and Connectivity

Diagnose and debug network issues efficiently:

ss -tulnp
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  • Lists open ports and listening services. 
ip route show
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  • Displays the system's routing table. 
nmap -sP 192.168.1.0/24
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  • Scans the local network for active devices. 
tcpdump -i eth0 port 80
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  • Captures network packets on the eth0 interface for HTTP traffic analysis. 
dig example.com +short
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  • Performs a DNS lookup to resolve domain names. 
nc -zv google.com 443
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  • Checks if a remote server's port is open.

🔄 3. Process and Job Management

Manage running processes and background jobs:

jobs -l
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  • Lists all background jobs. 
fg %1
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  • Brings job number 1 to the foreground. 
bg %1
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  • Resumes job 1 in the background. 
pkill -f "process_name"
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  • Kills a process by name. 
nohup command &
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  • Runs a command even after logging out.

🔒 4. Security and User Management

Enhance system security with these commands:

sudo visudo
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  • Edits the sudoers file securely. 
usermod -aG docker username
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  • Adds a user to the docker group. 
passwd -l username
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  • Locks a user account. 
find / -perm /4000 2>/dev/null
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  • Finds files with the SUID bit set (potential security risks). 
history | awk '{print $2}' | sort | uniq -c | sort -nr | head -10
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  • Displays the top 10 most used commands.

💾 5. Disk Management and File Operations

Efficiently manage disk space and files:

lsblk
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  • Lists storage devices and partitions. 
mount | column -t
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  • Displays mounted filesystems in a readable format. 
du -ah /var/log | sort -rh | head -10
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  • Shows the top 10 largest log files. 
rsync -avzh source/ destination/
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  • Syncs files between directories or servers efficiently. 
tar -czvf backup.tar.gz /path/to/backup
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  • Compresses a directory into a .tar.gz file.

🚀 6. DevOps-Specific Commands

Essential commands for CI/CD, Docker, Kubernetes, and Terraform:

docker ps -a
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  • Lists all running and stopped Docker containers. 
docker images
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  • Displays locally stored Docker images. 
kubectl get pods --all-namespaces
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  • Lists all Kubernetes pods across namespaces. 
kubectl logs -f pod-name
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  • Streams logs from a Kubernetes pod. 
terraform fmt && terraform validate
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  • Formats and validates Terraform configuration. 
ansible-playbook -i inventory playbook.yml --check
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  • Runs an Ansible playbook in dry-run mode. 
git log --oneline --graph --all
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  • Displays a graphical representation of Git commit history.

🤖 7. Automation and Scheduling

Automate tasks and schedule jobs:

watch -n 5 df -h
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  • Runs df -h every five seconds. 
alias ll='ls -lah'
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  • Creates a shortcut for ls -lah. 
crontab -l
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  • Lists scheduled cron jobs. 
at 10:30 PM tomorrow
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  • Schedules a command to run at a specific time.

🔥 Final Thoughts

Mastering these advanced Linux commands will elevate your DevOps skills, helping you debug issues, automate workflows, and optimize performance.

💬 Which Linux command do you find most useful in your DevOps journey? Let’s discuss in the comments! 🚀

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