Essential Linux Commands Every DevOps Engineer Should Know (Part 1, 2025 Edition)

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Linux remains the backbone of modern DevOps, cloud, and infrastructure engineering. Whether you’re deploying applications, managing servers, or automating CI/CD pipelines, you’ll constantly rely on the Linux command line.

As a DevOps engineer, mastering these commands boosts efficiency, ensures better troubleshooting, and improves collaboration across teams. This guide updates the essential Linux commands for 2025, including newer tools that have replaced older utilities in modern distributions.

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Understanding Linux Symbols

$( ) – Command Substitution

Used to capture the output of one command and pass it to another:

echo "Today is $(date)"

$ – Variables & Environment

• Prompt: $ indicates a non-root shell prompt.
• Variables: echo $HOME prints the current user’s home directory.
• Process ID: $! references the PID of the last background process.

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System Information

uname – Kernel Information

uname -a

Shows kernel version and system architecture.

lsb_release – Distro Info

For Debian/Ubuntu-based systems:

lsb_release -a

hostnamectl – Host Information (modern replacement for hostname)

hostnamectl

top / htop – Process Monitoring

• top: Built-in, basic monitoring.
• htop: Interactive, colorized, easier navigation (install separately).

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File & Directory Management

ls – List Files

ls -lh

• -l = long format
• -h = human-readable sizes

cd – Change Directory

cd /var/log
cd ..      # up one level
cd ~       # home directory

mkdir & rmdir – Create/Remove Directories

mkdir -p newdir/subdir
rmdir emptydir

touch – Create/Update File

touch newfile.txt

rm – Remove Files

rm file.txt
rm -rf directory/

⚠️ Always use caution with rm -rf.

cp & mv – Copy and Move Files

cp file.txt /backup/
mv oldname.txt newname.txt

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System Maintenance

reboot & shutdown

sudo reboot
sudo shutdown -h now

df – Disk Space

df -h

du – Disk Usage

du -sh /var/log/*

ps & kill

ps aux | grep nginx
sudo kill -9 <PID>

Modern replacement: systemctl for managing services.

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User & Group Management

User Commands

sudo useradd -m -s /bin/bash username
sudo passwd username
sudo userdel username

Group Commands

sudo groupadd devops
sudo usermod -aG devops username

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Package Management

• Debian/Ubuntu:

  sudo apt update && sudo apt upgrade
  sudo apt install nginx
  

• RHEL/CentOS/Fedora:

  sudo dnf install nginx
  

• Arch Linux:

  sudo pacman -Syu
  

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Text Editors

• nano – Simple editor (nano file.txt)
• vim – Powerful modal editor (vim file.txt)
• emacs – Customizable editor (emacs file.txt)

For DevOps workflows, vim remains the most common due to server availability.

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Networking Commands

ip – Modern Replacement for ifconfig

ip addr show
ip route show

ss – Modern Replacement for netstat

ss -tuln

Connectivity Tools

ping google.com
traceroute github.com
dig openai.com

Firewall Management

sudo ufw status     # Ubuntu
sudo firewall-cmd --list-all   # RHEL/CentOS

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Conclusion

Learning Linux commands is non-negotiable for DevOps engineers. From managing systems to debugging containers and automating deployments, these commands are the building blocks of productivity.

• Prefer ip and ss over legacy tools like ifconfig and netstat.
• Use htop for better monitoring.
• Master package managers (apt, dnf, pacman).
• Always follow best practices for security and automation.

Linux isn’t just an OS; it’s a DevOps superpower. Master these essentials, and you’ll be ready to handle any production challenge. 🚀

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