Networking Commands in Linux

Networking is a pivotal part of Linux system administration. Below is an explanation of some crucial networking commands:

  • ping host: Sends ICMP ECHO_REQUEST packets to a host to test connectivity and measure response time.
  • whois domain: Queries WHOIS databases to retrieve domain registration information.
  • dig domain: Queries DNS servers for information about domain name resolutions and other DNS records.
  • netstat -pnltu: Displays various network information, including active connections, listening ports, and protocol statistics.
  • ifconfig: Displays the configuration of the system’s network interfaces, including IP addresses.
  • ssh user@host: Initiates a secure shell connection to a remote host as the specified user.
  • scp: Securely copies files between hosts over the SSH protocol.
  • wget url: Downloads files from the Internet using HTTP, HTTPS, and FTP protocols.
  • curl url: Transfers data to or from a server using various protocols and can be used to request URLs.
  • traceroute domain: Traces the path packets take from the local machine to the remote domain.
  • mtr domain: Combines the functionality of traceroute and ping to provide a comprehensive network diagnostic tool.
  • ss: A utility that provides information about sockets. It is used as a modern replacement for netstat.
  • nmap: A powerful network scanner used to discover devices and services on a computer network and for security auditing.

Archives and Compression Commands

Handling file compression and archives is often necessary for data storage and transfer:

  • tar cf file.tar files: Creates an archive file named file.tar containing the specified files or directories.
  • tar xf file.tar: Extracts the files from an archive named file.tar.
  • gzip file: Compresses the specified file and renames it to file.gz.
  • gzip -d file.gz: Decompresses file.gz back to its original format.
  • zip -r file.zip files: Creates a compressed zip archive named file.zip.
  • unzip file.zip: Extracts the contents of the zip archive.

Text Processing Commands

Text processing is an everyday task in Linux. Here are some commands used to search and manipulate text:

  • grep pattern files: Searches for a specific pattern in files.
  • grep -r pattern dir: Recursively search for a pattern within a directory.
  • command | grep pattern: Pipes the output of a command into grep to search for a pattern.
  • echo 'text': Outputs the text to the terminal.
  • sed 's/string1/string2/g' filename: Replaces occurrences of string1 with string2 in a file.
  • diff file1 file2: Shows the differences between two files.
  • wc filename: Counts the lines, words, and characters in a file.
  • awk: A programming language used for text processing and manipulation.
  • sed -i 's/string1/string2/g' filename: Similar to sed but edits the file in place without requiring output redirection.
  • cut -d':' -f1 /etc/passwd: Cuts out and displays the first field of each line in /etc/passwd, using colon as the delimiter.

Disk Usage Commands

Monitoring disk usage is essential for maintaining system health:

  • df: Displays the amount of disk space used and available on all mounted filesystems.
  • du: Shows the disk space used by directories.
  • free: Shows the amount of free and used memory in the system, including swap.
  • whereis app: Searches for possible locations of an application.

System Information Commands

Gathering system information is often necessary for troubleshooting and system monitoring:

  • date: Displays or sets the system date and time.
  • cal: Displays a calendar of the current month.
  • uptime: Shows how long the system has been running.
  • w: Displays who is currently logged in and their activity.
  • whoami: Displays the username of the current user.
  • uname -a: Provides a wide range of system information, including the kernel name, version, and other details.
  • df -h: Shows disk space usage in a human-readable format.
  • du -sh: Displays the disk usage of the current directory in a human-readable format.
  • free -m: Displays the amount of free and used memory in megabytes.

These commands are fundamental for managing network resources, data compression, text processing, disk utilization, and retrieving system information. They provide a solid foundation for Linux users to perform various tasks effectively.

Tags: