Linux Basic Commands Cheat Sheet: A Quick Reference Guide

Cheat Sheet in Image Format

Essential Linux Commands with Examples

Linux commands are the backbone of managing and interacting with a Linux-based operating system. Whether you're a beginner or an advanced user, mastering these commands can greatly enhance your productivity. Below is a list of essential commands categorized with their descriptions and examples.

---

1. File and Directory Commands

ls – List Files and Directories

Displays the files and directories in the current directory.

ls            # Basic listing
ls -l         # Detailed listing with permissions
ls -a         # Include hidden files

Example:
If you run ls -l in /home/user, it might display:

-rw-r--r--  1 user user  1234 Jan 25 10:00 file.txt
drwxr-xr-x  2 user user  4096 Jan 25 09:30 my_folder

---

cd – Change Directory

Moves to a specified directory.

cd /home/user/documents    # Go to 'documents' folder
cd ..                      # Move one level up
cd ~                       # Go to the home directory

Example:

cd /var/log
pwd    # Output: /var/log

---

mkdir – Create a Directory

Creates a new folder.

mkdir new_folder

Example:
Running mkdir projects creates a folder named projects in the current directory.

---

pwd – Print Working Directory

Displays the full path of your current directory.

pwd

Example:
If you're in /home/user, the output will be:

/home/user

---

2. File Operations

touch – Create a File

Creates an empty file.

touch myfile.txt

Example:
Running touch report.txt creates an empty file named report.txt in the current directory.

---

cp – Copy Files

Copies files or directories.

cp source.txt destination.txt    # Copy file
cp -r source_folder/ dest_folder/ # Copy directory

Example:

cp file.txt backup/    # Copies file.txt into the backup folder

---

mv – Move or Rename Files

Renames or moves a file or directory.

mv oldname.txt newname.txt    # Rename file
mv file.txt /destination/     # Move file

Example:

mv report.txt ~/documents/    # Moves report.txt to the documents folder

---

rm – Remove Files

Deletes files or directories.

rm file.txt           # Remove a file
rm -r folder_name     # Remove a folder

Example:

rm old_file.txt    # Deletes the file named old_file.txt

---

3. Viewing File Contents

cat – Display File Contents

Shows the content of a file.

cat file.txt

Example:
If file.txt contains "Hello, World!", running cat file.txt will display:

Hello, World!

---

grep – Search Within Files

Searches for specific patterns in a file.

grep "text" file.txt    # Case-sensitive search
grep -i "text" file.txt # Case-insensitive search

Example:

grep "error" log.txt    # Searches for the word "error" in log.txt

---

4. User Management

whoami – Display Current User

Shows the username of the logged-in user.

whoami

Example:
Running whoami might output:

john

---

5. Process Management

ps – Display Running Processes

Lists active processes.

ps
ps aux    # Displays all processes in detail

Example:

ps aux | grep firefox    # Finds all processes related to Firefox

kill – Terminate Processes

Stops a process by its process ID (PID).

kill PID

Example:

kill 12345    # Terminates the process with PID 12345

---

6. Disk and System Information

df – Display Disk Usage

Shows how much disk space is used and available.

df -h    # Human-readable format

Example:

Filesystem      Size  Used Avail Use% Mounted on
/dev/sda1       50G   20G   30G  40% /

---

uname – System Information

Displays details about the operating system.

uname -a

Example:

Linux mypc 5.15.0-50-generic #55~20.04.1-Ubuntu SMP x86_64 GNU/Linux

---

7. Networking Commands

ping – Test Network Connectivity

Checks the connection to a host.

ping google.com

Example:

PING google.com (142.250.182.14): 56 data bytes
64 bytes from 142.250.182.14: icmp_seq=0 ttl=115 time=22.3 ms

---

curl – Fetch Data from a URL

Transfers data from or to a server.

curl https://example.com

Example:
Running curl https://api.github.com fetches API data from GitHub.

---

Conclusion

This cheat sheet provides a handy reference to commonly used Linux commands. With these commands, you can easily manage files, processes, users, and networks on your Linux system. Bookmark this for quick access, and let me know if you’d like more commands or tips!