Essential Linux Commands for Cloud Developers: From Basics to Advanced

1. Introduction

In this post, I'll walk you through must-know Linux commands for both cloud beginners and advanced cloud engineers — with real-world use cases.

2. Basic Linux Commands for Cloud Beginners

These are the foundational commands used in almost every cloud instance:

🔹 Navigation & File Management

• cd /var/log — Navigate to log directory
• ls -l — List files in long format
• pwd — Print working directory
• mkdir /data — Create new directory
• cp file.txt /data/ — Copy file
• mv file.txt /data/ — Move file
• rm file.txt — Remove file

🔹 File Viewing & Editing

• cat file.txt — View file contents
• less file.txt — Scroll through long files
• tail -f app.log — Live view of logs
• nano config.yaml — Edit file with nano (press I for insert mode)
• vi config.yaml — Edit file with vi (more advanced)

🔹 Logs & Troubleshooting

• journalctl -xe — View system logs (systemd)
• tail -f /var/log/syslog — Live logs from syslog
• dmesg — Kernel logs (often useful for hardware issues)
• cat /var/log/auth.log — Authentication logs
• grep "ERROR" logfile.log — Search for specific log lines

🔹 User and Permissions

• adduser username — Create new user
• passwd username — Set/change password
• usermod -aG sudo user — Add user to sudo group
• whoami — Show current user
• id — Show user and group IDs
• chmod +x script.sh — Make script executable
• chown user:group file.txt — Change ownership

🔹 System Info & Monitoring

• df -h — Disk space usage
• free -m — Memory usage
• uptime — System load and uptime
• top — Live process monitor
• ps aux — List all processes

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3. Advanced Linux Commands for Cloud & DevOps

🔸 Networking & Connectivity

• ip a — Show network interfaces and IPs
• ip r — Show routing table
• netstat -tulnp — Show listening ports (use ss as alternative)
• curl https://example.com — Make HTTP request (useful for testing)
• telnet host 80 — Test connectivity to a port
• ping 8.8.8.8 — Check internet connection
• traceroute google.com — Track route to a host
• dig domain.com — DNS lookup
• nslookup domain.com — Another DNS lookup tool
• telnet host port — Test if a port is open
• nmap host — Scan open ports (if installed)

🔸 Process & Resource Management

• htop — Better version of top (if installed)
• kill -9 PID — Kill a process forcefully
• nice -n 10 cmd — Run a command with a priority

🔸 Package Management (Ubuntu / Debian-based)

• sudo apt update && sudo apt upgrade — Update system
• apt install htop — Install package
• apt remove <pkg> — Remove a package
• dpkg -l — List installed packages
• which <command> — Show path of a binary (Use yum, dnf, or zypper for RHEL/CentOS/openSUSE systems)

🔸 SSH & Remote Access

• ssh user@ip-address — Connect to remote server
• scp file.txt user@host:/dir — Copy file over SSH
• rsync -avz /src/ /dest/ — Efficient file sync
• ssh-keygen — Generate SSH key pair
• ssh-copy-id user@host — Add your key to remote authorized_keys

🔸 Disk and Filesystem

• lsblk — List block devices
• mount /dev/sdb1 /mnt/data — Mount a disk
• df -Th — Show disk with filesystem types
• du -sh * — Show directory sizes

🔸 Systemd and Services

• systemctl status nginx — Check service status
• systemctl start nginx — Start a service
• systemctl enable nginx — Enable on boot
• journalctl -u nginx — View logs for a service

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4. Scripting & Automation in the Cloud

🔹 Shell Scripts for Automating Tasks

bash
#!/bin/bash
# update_and_restart.sh
sudo apt update && sudo apt upgrade -y
sudo systemctl restart nginx

Run it:
chmod +x update_and_restart.sh
./update_and_restart.sh

You can mention cron jobs (crontab -e) for scheduled tasks.
`crontab -e`     --Edit cron jobs (automated tasks)
`env`            --Show environment variables
`bash script.sh` --Run shell script

🧵 ## 5. Real-World Use Cases (Optional Section)
Include mini examples like:

🔹**Check disk space before deploying to EC2:**
ssh ec2-user@ip 'df -h'

🔹**Copy logs from a VM to local:**
scp ec2-user@ip:/var/log/app.log ./logs/

🔹**Restart a service via SSH:**
ssh user@host 'sudo systemctl restart nginx'

🧾 ## 6. Conclusion
Whether you're a junior developer learning cloud or a seasoned engineer managing production infrastructure, mastering Linux commands will save you time, stress, and mistakes.

These commands form the backbone of day-to-day tasks in cloud computing — from debugging apps to automating deployments.

💬 What’s your go-to Linux command in the cloud? Share it below!
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