11 August 2025

Comprehensive Linux Command Cheat Sheet

by Dan.C

Cover Image

🐧 Linux Command Cheat Sheet

A curated reference guide to the most essential Linux commands — ideal for system administrators, developers, DevOps engineers, and cybersecurity professionals. Whether you’re a beginner or brushing up your skills, this categorized cheat sheet will help streamline your command-line workflow.

Table of Contents

  1. Introduction
  2. File and Directory Operations
  3. Viewing & Editing Files
  4. Permissions & Ownership
  5. System Information
  6. User & Process Management
  7. Networking Commands
  8. Package Management
  9. Searching Files
  10. Keyboard Shortcuts & History
  11. Notes

🔍 File and Directory Operations

Command Description
ls List contents of the current directory
ls -l List with detailed (long) format
cd /path/to/dir Change current directory
pwd Display present working directory
mkdir new_folder Create a new directory
rm file.txt Remove a file
rm -r folder/ Recursively remove a directory and its contents
touch file.txt Create a new, empty file
cp source dest Copy a file or directory
mv old new Move or rename a file or directory

🛠️ Viewing & Editing Files

Command Description
cat file.txt Output file contents to the terminal
less file.txt View file one screen at a time (scrollable)
head file.txt Show the first 10 lines of a file
tail file.txt Show the last 10 lines of a file
nano file.txt Edit file using Nano (beginner-friendly)
vim file.txt Edit file using Vim (advanced editor)

📁 Permissions & Ownership

Command Description
chmod +x script.sh Make a script executable
chmod 755 file Set read/write/execute permissions (owner), and read/execute (group, others)
chown user:group file Change file ownership

🧠 System Information

Command Description
uname -a Show system and kernel information
top / htop Real-time process and system monitoring
df -h Display disk space usage (human-readable)
free -h Show memory usage
uptime Show how long the system has been running

🔐 User & Process Management

Command Description
whoami Display current logged-in user
id Show user ID (UID), group ID (GID), and groups
ps aux List all running processes
kill PID Terminate a process by its PID
sudo command Run command with superuser privileges
adduser username Add a new user
passwd username Change a user’s password

🌐 Networking Commands

Command Description
ip a Display network interfaces and IP addresses
ping domain.com Send ICMP packets to test connectivity
curl https://example.com Fetch data from a URL
netstat -tulpn Show active listening ports and services (legacy; use ss for modern systems)
ssh user@host Connect to a remote host via SSH

🧹 Package Management

📦 Debian/Ubuntu (APT)

Command Description
sudo apt update Update package lists
sudo apt upgrade Upgrade installed packages
sudo apt install package Install a new package
sudo apt remove package Remove a package

📦 Red Hat/CentOS (YUM/DNF)

Command Description
sudo yum install package Install package (YUM)
sudo dnf upgrade Upgrade packages (DNF, successor to YUM)

📝 Searching Files

Command Description
find / -name file.txt Search for a file by name starting from root
grep 'pattern' file.txt Search for a text pattern in a file
locate file.txt Quickly find file paths using an indexed database (updatedb required)

💡 Keyboard Shortcuts & History

Shortcut Description
Ctrl + C Cancel the current running process
Ctrl + D Logout of terminal or send EOF (End of File)
Ctrl + R Search command history interactively
!! Repeat the last command
!abc Run the most recent command starting with abc

📎 Notes

Stay efficient. Stay secure.

tags: linux - terminal - cheat-sheet - command-line - sysadmin - devops