Linux Cheat Sheet

Linux Cheat Sheet

Whether you’re a beginner getting your hands dirty or a seasoned sysadmin managing hundreds of servers, mastering the Linux command line is a must.

This article will guide you through:

• Application and Package Management
• Console and Output Management
• Environment Variables
• File and Directory Operations
• Networking Essentials
• Process and System Control
• Common Compound Operations
• Useful Lookup and Diagnostic Tools
• Realistic Usage Scenarios
• Key Best Practices and Takeaways

Let’s dive into each section with practical examples and clear explanations.

Application and Package Management

which

Shows the full path of an installed command.

which clear

dnf / yum

Install, list, remove, and manage packages on RHEL-based systems.

sudo dnf install net-tools
sudo yum remove net-tools
sudo yum list net-tools

Console and Output Management

cat

Displays the contents of a file.

cat /etc/system-release

clear

Clears the terminal screen.

clear

echo

Prints text to the screen or writes to a file.

echo "Hello"
echo "data" >> file.txt

top

Shows active processes and system performance.

top

more

Views large files one page at a time.

cat /var/log/audit/audit.log | more

man

Displays manual pages for a command.

man grep

Environment Variables

env

Lists all current environment variables.

env

export

Sets and exports an environment variable.

export MY_VAR="1907"

printenv

Prints the value of a specific environment variable.

printenv USER

source

Executes a script in the current shell.

source ~/.bashrc

File and Directory Operations

cd

Changes the current directory.

cd /home/

cp

Copies files or directories.

cp file1.txt file2.txt

mv

Moves or renames files or directories.

mv oldname.txt newname.txt

rm

Deletes files or directories.

rm file.txt
rm -r directory/

mkdir

Creates a new directory.

mkdir new_folder

ls

Lists files and directories.

ls
ls -lart

pwd

Prints the current working directory.

pwd

find

Searches for files and directories.

find / -name filename.txt

grep

Searches for patterns within files.

grep "PATH" ~/.bashrc

tar

Compresses or extracts files from archives.

tar -czvf archive.tar.gz folder/
tar -xzvf archive.tar.gz

Networking Essentials

curl

Transfers data from or to a server.

curl https://example.com

wget

Downloads files from the web.

wget http://example.com/file.zip

ip

Displays or manipulates IP configuration.

ip a

ifconfig

Legacy command to display network interfaces.

ifconfig

netstat

Displays network connections, routing tables, etc.

netstat -tulnpa

ss

Displays detailed socket statistics.

ss -tuln

nslookup

Performs DNS lookups.

nslookup google.com

traceroute

Traces the route packets take to a host.

traceroute google.com

ssh

Connects securely to remote machines.

ssh user@***.ipadres.****

Process and System Control

ps

Displays information about active processes.

ps aux

kill

Terminates processes by PID.

kill 1234

poweroff

Shuts down the machine.

sudo poweroff

reboot

Restarts the machine.

sudo reboot

whoami

Prints the current user’s username.

whoami

hostname

Displays or sets the system hostname.

hostname

Common Compound Operations

&&

Runs multiple commands sequentially only if the previous succeeds.

mkdir test && cd test

Realistic Usage Scenarios

Check system version:

cat /etc/system-release

Download a file from the web:

wget https://www.google.com

Compress a folder:

tar -czvf backup.tar.gz myfolder/

Search for IP configuration:

ip a | grep inet

Kill a stuck process:

ps aux | grep myapp
kill <PID>

Key Best Practices and Takeaways

• Use man <command> to learn more about any tool.
• Prefer dnf over yum on newer RHEL-based systems.
• Use && to chain dependent commands safely.
• Use source to reload environment settings without logging out.
• Always double-check before using rm -r to avoid irreversible deletion.

Conclusion

This cheat sheet is your foundation for becoming efficient in the Linux terminal. Each command here is a powerful tool in your daily toolkit — whether you’re editing files, managing packages, debugging networks, or controlling processes. Save this guide, refer back often, and continue exploring what the CLI can do for you.