Linux and Networking Commands Basics

Basic Linux Commands

• ls command lists directory contents
• cd command changes the directory
• pwd command prints the working directory
• cp command copies files/directories
• mv command moves/renames files/directories
• rm command removes files/directories
• chmod command changes file mode bits (permissions)
• chown command changes file owner and group
• grep command searches text using patterns

Networking Commands

• ifconfig and ip addr commands display network interfaces and IP addresses
• ping command checks connectivity to a host
• netstat command displays network connections, routing tables, and interface statistics
• ss command is a utility to investigate sockets
• traceroute command traces the route packets take to a network host
• nslookup and dig commands query Internet name servers for DNS information

Ports and Protocols

• HTTP uses port 80 for web traffic
• HTTPS uses port 443 for secure web traffic
• FTP uses port 21 for file transfers
• SSH uses port 22 for secure remote administration
• SMTP uses port 25 for email sending
• DNS uses port 53 for domain name resolution
• DHCP uses ports 67 and 68 for network device configuration
• RDP uses port 3389 for Windows remote desktop access

TCP and UDP Protocols

• TCP (Transmission Control Protocol) is a connection-oriented protocol, ensuring messages are delivered in order and checks for errors, like making a phone call
• UDP (User Datagram Protocol) is a connectionless protocol, sending data without establishing a connection, making it faster but without guarantees for delivery or order, suitable for streaming where speed is preferred over reliability

Test your knowledge on basic Linux commands such as ls, cd, cp, and networking commands like ifconfig, ping, netstat. Practice using common commands for file/directory operations and network troubleshooting.