Linux Tutorial: Essential Linux Commands

Gopi Pacha

— 3 min read
Linux Tutorial: Essential Linux Commands

A comprehensive guide to the most important Linux commands.

File & Directory Navigation

cd - Change Directory

Navigate between directories in your filesystem.

cd /home/user/documents    # Go to specific path
cd ..                      # Go up one level
cd ~                       # Go to home directory

ls - List Directory Contents

Display files and folders in the current directory.

ls                # Basic listing
ls -la            # Detailed listing with hidden files
ls -lh            # Human-readable file sizes

pwd - Print Working Directory

Show the current directory path you're in.

pwd    # Displays: /home/user/documents

File Operations

mkdir - Make Directory

Create new directories/folders.

mkdir newfolder              # Create single directory
mkdir -p path/to/nested/dir  # Create nested directories

touch - Create Empty File

Create new empty files or update timestamps.

touch newfile.txt
touch file1.txt file2.txt file3.txt

cp - Copy Files/Directories

Copy files and directories from one location to another.

cp source.txt destination.txt     # Copy file
cp -r folder1/ folder2/           # Copy directory recursively

mv - Move/Rename Files

Move or rename files and directories.

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

rm - Remove Files/Directories

Delete files and directories permanently.

rm file.txt              # Remove file
rm -r folder/            # Remove directory recursively
rm -rf folder/           # Force remove (use carefully!)

File Viewing & Editing

cat - Concatenate and Display Files

Display entire file contents in the terminal.

cat file.txt
cat file1.txt file2.txt    # Display multiple files

less - View File with Pagination

View large files with scrolling capability.

less largefile.log    # Use arrow keys, 'q' to quit

head - View First Lines

Display the first 10 lines of a file.

head file.txt
head -n 20 file.txt    # Show first 20 lines

tail - View Last Lines

Display the last 10 lines of a file.

tail file.txt
tail -f application.log    # Follow live updates

nano - Simple Text Editor

Easy-to-use terminal text editor.

nano file.txt    # Edit file (Ctrl+X to exit)

Search & Find

grep - Search Text Patterns

Search for specific patterns within files.

grep "error" logfile.txt           # Find "error" in file
grep -r "TODO" .                   # Search recursively in directory
grep -i "warning" file.txt         # Case-insensitive search

find - Search for Files/Directories

Locate files and directories by name or properties.

find . -name "*.txt"              # Find all .txt files
find /home -type d -name "backup" # Find directories named "backup"

System Information

df - Disk Space Usage

Display available disk space on filesystems.

df -h    # Human-readable format

du - Directory Size

Show disk usage of files and directories.

du -sh folder/    # Summary of folder size
du -h --max-depth=1    # Size of subdirectories

top - Process Monitor

Display running processes and system resource usage.

top    # Press 'q' to quit

ps - Process Status

Show currently running processes.

ps aux              # All processes with details
ps aux | grep nginx # Find specific process

Permissions & Ownership

chmod - Change File Permissions

Modify file/directory access permissions.

chmod 755 script.sh    # rwxr-xr-x
chmod +x script.sh     # Make executable

chown - Change Ownership

Change file/directory owner and group.

sudo chown user:group file.txt
sudo chown -R user:group folder/

Network & Connectivity

ping - Test Network Connectivity

Check if a host is reachable.

ping google.com
ping -c 4 192.168.1.1    # Send 4 packets

curl - Transfer Data from URLs

Download files or interact with web services.

curl https://example.com
curl -O https://example.com/file.zip    # Download file

wget - Download Files

Download files from the internet.

wget https://example.com/file.zip
wget -c https://example.com/largefile.iso    # Resume download

System Administration

sudo - Execute as Superuser

Run commands with administrative privileges.

sudo apt update
sudo systemctl restart nginx

apt / yum - Package Manager

Install, update, and remove software packages.

sudo apt update              # Update package list (Debian/Ubuntu)
sudo apt install package     # Install package
sudo yum install package     # Install package (RHEL/CentOS)

systemctl - Service Management

Control system services (start, stop, restart).

sudo systemctl start nginx
sudo systemctl status apache2
sudo systemctl enable docker    # Enable on boot

tar - Archive Files

Compress and extract archive files.

tar -czvf archive.tar.gz folder/    # Create compressed archive
tar -xzvf archive.tar.gz            # Extract archive

ssh - Secure Shell

Connect to remote servers securely.

ssh user@192.168.1.100
ssh -i keyfile.pem user@server.com

history - Command History

View previously executed commands.

history           # Show all commands
history | grep cd # Search command history

Pro Tips

  • Use Tab key for auto-completion
  • Use Ctrl + C to cancel running commands
  • Use Ctrl + R to search command history
  • Add --help or -h to any command for usage info
  • Use man command to read detailed manual pages