Linux Commands Cheat Sheet

Linux command line is essential for server management, DevOps, and development. This cheat sheet covers the most frequently used commands.

File Navigation

pwd                         # Current directory
ls -la                      # List all files with details
cd /path/to/dir             # Change directory
cd ~                        # Home directory
cd -                        # Previous directory

File Operations

cp file.txt backup.txt      # Copy
mv file.txt new.txt         # Move/rename
rm file.txt                 # Delete
rm -rf directory            # Delete directory recursively
mkdir -p dir/subdir         # Create directories
touch file.txt              # Create empty file
ln -s target link           # Create symlink

Viewing Files

cat file.txt                # Print file
less file.txt               # Scrollable view
head -n 20 file.txt         # First 20 lines
tail -n 20 file.txt         # Last 20 lines
tail -f log.txt             # Follow new lines
wc -l file.txt              # Count lines

Searching

find . -name "*.js"         # Find files by name
find . -type f -size +10M   # Files larger than 10MB
grep "pattern" file.txt     # Search in file
grep -r "pattern" .         # Recursive search
grep -i "pattern" file.txt  # Case insensitive
grep -n "pattern" file.txt  # Show line numbers

Permissions

chmod 755 script.sh         # rwxr-xr-x
chmod +x script.sh          # Add execute
chown user:group file.txt   # Change ownership
ls -l                       # View permissions

Process Management

ps aux                      # All processes
top                         # Live process monitor
kill PID                    # Kill process
kill -9 PID                 # Force kill
bg                          # Background last job
fg                          # Foreground last job
nohup command &             # Run after logout

Networking

curl https://example.com    # HTTP request
wget https://example.com    # Download file
ping google.com             # Test connectivity
netstat -tlnp               # Open ports
ss -tlnp                    # Open ports (modern)
ip addr                     # IP addresses

Text Processing

sort file.txt               # Sort lines
uniq file.txt               # Remove duplicates
cut -d',' -f1 file.csv      # Extract columns
awk '{print $1}' file.txt   # Print first column
sed 's/old/new/g' file.txt  # Replace text

Disk Usage

df -h                       # Disk space
du -sh *                    # Directory sizes
du -sh .                    # Current directory size

Useful Combos

# Count files in directory
ls | wc -l

# Find large files
find . -type f -size +100M -exec ls -lh {} ;

# Watch file for changes
watch -n 2 cat status.txt

# Search and replace in multiple files
find . -name "*.txt" -exec sed -i 's/old/new/g' {} ;

Tools

Use the Regex Tester to test grep patterns before running them on your files.