Comprehensive Guide to Essential Linux Commands

Essential Linux Commands: A Practical Guide

Linux's power lies in its command-line interface (CLI), making it a favorite among developers and system administrators. This guide covers the fundamental commands you'll need for effective system management.

Basic Navigation

pwd     # Print working directory
cd      # Change directory
cd ..   # Move up one level
cd ~    # Go to home directory

File and Directory Operations

Listing and Creating

ls      # List files and directories
ls -lah # Detailed list (long format, all files, human-readable sizes)
touch   # Create empty file
mkdir   # Create directory
mkdir -p # Create nested directories

Manipulating Files

cp file1 file2     # Copy files
cp -r dir1 dir2    # Copy directories recursively
mv old new         # Move or rename
rm file           # Delete file
rm -r dir         # Delete directory recursively

File Permissions

chmod 755 file    # Set permissions (rwxr-xr-x)
chmod u+x file    # Add execute permission for user
chown user:group file  # Change ownership

Text File Operations

Viewing Content

cat file          # Display entire file
less file         # Page through file
head -n 10 file   # Show first 10 lines
tail -n 10 file   # Show last 10 lines

Text Editing

nano: Beginner-friendly editor
vim: Advanced editor with powerful features
grep "term" file: Search within files
grep -i "term" file: Case-insensitive search

Process Management

ps aux           # List all processes
top             # Real-time process monitor
kill PID        # Terminate process by ID
killall name    # Terminate process by name

Network Operations

ip addr         # Show network interfaces
ping host       # Test connectivity
netstat -tuln   # Show network connections
ss             # Modern alternative to netstat

System Information

df -h           # Disk space usage
du -h           # Directory space usage
uname -a        # System information
uptime         # System uptime and load

Pro Tips

Use Tab completion to avoid typing full paths
Access command history with up/down arrows
Chain commands with && (AND) or || (OR)
Use man command for detailed documentation
Combine commands with pipes (|) for powerful operations

Remember: Linux commands are case-sensitive, and most can be modified with flags (options) that start with - or --. When in doubt, use --help or man to learn more about any command.

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