<div>

<p>This is an article about how to monitor network bandwidth usage on a Linux system, specifically focusing on using the <code>nload</code> utility. In this article, you will find information about installing and configuring <code>nload</code>, understanding its output, and utilizing it for real-time monitoring of your internet connection’s traffic.</p>
<h2>Introduction to Network Bandwidth Monitoring</h2>
<p>Monitoring network bandwidth is essential in managing resources efficiently, diagnosing performance issues, and ensuring that your system or server does not exceed the capacity of its network infrastructure. With a plethora of tools available, <code>nload</code> stands out due to its simplicity and real-time nature. This tool provides a clear visualization of incoming and outgoing data transfer rates on a per-network interface basis.</p>
<h2>What is Nload?</h2>
<img src="/img/article/nload_example.webp" title="nload - linux command line application" alt="nload example image" />
<p>Nload is an open-source utility designed for monitoring the incoming and outgoing traffic through network interfaces in real time. It runs from the command line, making it accessible even without a graphical user interface (GUI). With its straightforward yet informative display of bandwidth usage, <code>nload</code> is highly useful for system administrators and developers who need to keep track of their network resources.</p>
<h2>Installing Nload on Ubuntu</h2>
<p>To install nload on your Ubuntu machine, you first need to open the terminal. You can do this by pressing <code>Ctrl+Alt+T</code> or searching for “Terminal” in your applications menu.</p>
<p>Once the terminal is open, update the package list and install nload using the following commands:</p>
<pre><code class="language-bash">sudo apt-get update
sudo apt-get install nload
</code></pre>
<p>These steps ensure that you have the latest software packages available before installing <code>nload</code>.</p>
<h2>Configuring Nload</h2>
<p>After installation, <code>nload</code> can be launched simply by typing <code>nload</code> into your terminal and pressing Enter. However, for more customized monitoring, a configuration file exists where you can set up various options.</p>
<p>To modify the default settings or configure specific interfaces to monitor, navigate to <code>/etc/nload.conf</code>. You can edit this file using any text editor of your choice, such as <code>nano</code>, by running:</p>
<pre><code class="language-bash">sudo nano /etc/nload.conf
</code></pre>
<p>Within this configuration file, you will find numerous options that allow customization, including interface selection (<code>INTERFACE</code>), refresh rate (<code>REFRESH_INTERVAL</code>), and graph colors. To save changes and exit the text editor in <code>nano</code>, press <code>Ctrl+O</code>, then <code>Enter</code>, followed by <code>Ctrl+X</code>.</p>
<h2>Understanding Nload Output</h2>
<p>Upon launching nload with no arguments or after configuring settings, you will see a screen split into two sections: one for incoming data (down) and another for outgoing data (up). Each section contains:</p>
<ul>
<li><strong>Rate</strong>: The current rate of data transfer in kilobytes per second.</li>
<li><strong>Traffic</strong>: Total amount of traffic transferred since the start of monitoring.</li>
<li><strong>Peak</strong>: The highest recorded rate during the session.</li>
</ul>
<p>Below these metrics, you will find a graphical representation showing the current bandwidth usage as well as historical trends over time. This visualization helps identify spikes or patterns in network activity.</p>
<h2>Real-Time Monitoring with Nload</h2>
<p>To effectively use <code>nload</code>, it’s important to keep an eye on both real-time and long-term data trends. By default, nload updates its display every second, allowing you to observe fluctuations in traffic instantly. Pressing any key will pause the updates temporarily, which can be useful for examining detailed information at a specific moment.</p>
<p>For extended monitoring sessions, consider redirecting the output of <code>nload</code> to a log file using commands such as:</p>
<pre><code class="language-bash">sudo nload &gt; /var/log/network-monitor.log 2&gt;&amp;1 &amp;
</code></pre>
<p>This allows you to review bandwidth data over days or weeks without having to keep the terminal open continuously.</p>
<h2>Advanced Use Cases</h2>
<p>Beyond basic monitoring, <code>nload</code> can be integrated with other tools for more sophisticated analysis. For instance, combining it with <code>iftop</code> (another popular bandwidth monitor) could offer a comprehensive view of both overall traffic trends and individual connections consuming resources. Additionally, scripting capabilities allow automating the collection and processing of data for deeper insights.</p>
<h2>Conclusion</h2>
<p>Read this article to find out about how to install, configure, and utilize nload effectively on Ubuntu systems for real-time network monitoring purposes. With its straightforward interface and powerful features, <code>nload</code> stands as a reliable tool in any Linux user’s arsenal when it comes to keeping tabs on bandwidth usage and optimizing network performance.</p>
<p>By following the steps outlined here, you can start tracking your network traffic immediately, helping ensure that your system operates within optimal conditions and avoids potential bottlenecks.</p>

</div>

This article details how to monitor network bandwidth using the `nload` utility in Ubuntu's terminal. It covers installation via the package manager, configuration through editing `/etc/nload.conf`, and interpretation of real-time traffic data displayed for both incoming and outgoing rates. Users can customize settings like interface selection and refresh intervals, and utilize output redirection for long-term monitoring. Advanced users may integrate `nload` with other tools or scripts to gain deeper insights into network performance and optimize resource usage effectively.

How to Monitor Network Bandwidth Using Nload on the Terminal in Ubuntu

<div>

<p>This is an article about how to use the <code>ping</code> command from the terminal to test network connectivity between your computer and a server. In this article, you will find information on various aspects of pinging servers, including understanding what ping does, why it’s useful, common syntax for issuing ping commands, and troubleshooting tips.</p>
<h2>Introduction</h2>
<p>The term “ping” in networking refers to sending data from one host to another (the destination) on an Internet Protocol network. It is often used as a test to determine if the network connection between two devices is functional or not. This article will focus specifically on using <code>ping</code> in Ubuntu Linux systems.</p>
<h2>What Is Ping?</h2>
<img src="/img/article/ping_google.webp" title="ping - linux command line application" alt="ping example image" />
<p>Ping is an essential tool for checking whether a specific IP address or hostname can be reached over a TCP/IP-based network. When you ping another device, your computer sends out a small packet of data to the target and waits for a response. This process allows you to verify if there’s a direct route between two points in a network.</p>
<h3>Why Use Ping?</h3>
<p>Using <code>ping</code> is crucial for diagnosing network problems such as determining whether an IP address or domain name can be reached, checking the responsiveness of a server, validating the integrity of your local connection, and troubleshooting connectivity issues.</p>
<h2>Prerequisites</h2>
<p>Before you start pinging servers from the terminal in Ubuntu, ensure that your system meets these requirements:</p>
<ul>
<li>You have access to an Ubuntu-based operating system.</li>
<li>Terminal is accessible on your device. On most Linux distributions, including Ubuntu, the default terminal application can be used for issuing commands.</li>
<li>Basic knowledge of command-line interfaces and networking concepts will help you understand this article better.</li>
</ul>
<h2>How Does Ping Work?</h2>
<p>When you ping a server or IP address from your terminal in Ubuntu:</p>
<ol>
<li>Your computer sends an ICMP (Internet Control Message Protocol) Echo Request to the target device.</li>
<li>The target device receives the request, processes it, and responds with an Echo Reply message back to the sender.</li>
<li>You receive information about how long each packet took to travel between devices.</li>
</ol>
<p>This round trip time is commonly known as latency and can be useful in understanding network performance.</p>
<h2>Basic Syntax of Ping Command</h2>
<p>The fundamental command for pinging a server or IP address from your Ubuntu terminal follows this basic structure:</p>
<pre><code class="language-bash">ping [options] destination
</code></pre>
<p>Where <code>[options]</code> refer to additional parameters you may want to set, such as the number of packets sent, waiting time between packets, etc., and <code>destination</code> represents either an IP address or a hostname.</p>
<h3>Simple Example</h3>
<p>To ping Google’s public DNS server (8.8.8.8), open your terminal and type:</p>
<pre><code class="language-bash">ping 8.8.8.8
</code></pre>
<p>Press Enter to execute the command. This will continuously send ICMP Echo Requests until you interrupt the process by pressing <code>Ctrl + C</code>.</p>
<h2>Common Ping Command Options</h2>
<p>The <code>ping</code> utility offers several options that allow for more precise control over how and when it communicates with a target server:</p>
<ul>
<li><code>-c count</code>: Specifies the number of packets to be sent (e.g., <code>ping -c 5 google.com</code>).</li>
<li><code>-i interval</code>: Sets the time in seconds between sending each packet.</li>
<li><code>-w deadline</code>: Stops pinging after a specified amount of time has elapsed (measured in seconds).</li>
<li><code>-q</code>: Enables quiet mode, reducing output and suppressing per-packet statistics.</li>
</ul>
<p>Example:</p>
<pre><code class="language-bash">ping -c 10 google.com
</code></pre>
<p>This command will send ten packets to Google’s domain name and then stop automatically.</p>
<h2>Advanced Usage</h2>
<p>Beyond basic pinging, there are several advanced techniques you can employ using the <code>ping</code> utility:</p>
<h3>Pinging Multiple Hosts</h3>
<p>To ping multiple hosts simultaneously or sequentially, list them separated by spaces after specifying any desired options. For example,</p>
<pre><code class="language-bash">ping -c 3 google.com yahoo.com bing.com
</code></pre>
<p>This will send three packets to each domain in sequence.</p>
<h3>Using Ping for Network Diagnostics</h3>
<p>If you suspect network problems, you can use <code>ping</code> creatively:</p>
<ul>
<li>
<p><strong>Check Local Connectivity</strong>: Before attempting to ping remote servers, ensure your local connection works by pinging the loopback address (<code>127.0.0.1</code>).</p>
<pre><code class="language-bash">ping -c 4 localhost
</code></pre>
</li>
<li>
<p><strong>Verify DNS Resolution Issues</strong>: If you cannot reach a server via its domain name but know its IP address, try pinging it directly to distinguish between network and DNS issues.</p>
<pre><code class="language-bash">ping google.com &amp;&amp; ping 8.8.8.8
</code></pre>
</li>
</ul>
<h3>Pinging with Different Protocols</h3>
<p>While <code>ping</code> primarily uses ICMP, you can also use similar tools like <code>traceroute</code>, <code>telnet</code>, or even specific protocol pings (e.g., TCP) for deeper diagnostics.</p>
<h2>Interpreting Ping Results</h2>
<p>When interpreting the output of your ping command in Ubuntu, focus on these key metrics:</p>
<ul>
<li><strong>Time</strong>: The time taken for each round trip.</li>
<li><strong>Packet Loss</strong>: Indicates whether packets did not reach their destination and were consequently lost. High packet loss often suggests network congestion or misconfiguration.</li>
<li><strong>Round Trip Time (RTT)</strong>: A measure of the responsiveness of a server, showing how long it takes on average for your data to get there and back again.</li>
</ul>
<h2>Troubleshooting with Ping</h2>
<h3>Common Issues</h3>
<ol>
<li><strong>Ping Response Too Slow</strong>: If pinging returns very slow responses or no replies at all, suspect network congestion.</li>
<li><strong>Unreachable Destination</strong>: Confirm that the destination is reachable either through DNS resolution issues or physical connectivity problems.</li>
<li><strong>Incorrect Options Used</strong>: Ensure proper use of ping command options according to your needs.</li>
</ol>
<h3>Resolving Issues</h3>
<ul>
<li>Review firewall settings and ensure they aren’t blocking ICMP traffic.</li>
<li>Verify network cables and physical connections if necessary.</li>
<li>Test with different servers or devices to pinpoint the source of failure.</li>
</ul>
<h2>Conclusion</h2>
<p>Understanding how to utilize <code>ping</code> effectively from the terminal in Ubuntu is invaluable for troubleshooting network connectivity issues. By mastering the basic syntax, options, and interpreting results accurately, you enhance your ability to maintain smooth communication across networks. Whether you’re a beginner navigating through Linux commands or an experienced user refining diagnostic techniques, <code>ping</code> remains one of the most powerful tools available at your disposal.</p>
<h3>Next Steps</h3>
<p>After learning how to ping effectively:</p>
<ul>
<li>Explore other network diagnostics utilities like traceroute and mtr.</li>
<li>Consider using graphical network tools for more detailed analysis and visualization.</li>
<li>Deepen your knowledge about TCP/IP protocols and their roles in communication.</li>
</ul>

</div>

This article details the use of the `ping` command in Ubuntu Linux to test network connectivity. It covers understanding what ping does, its utility, common syntax, troubleshooting tips, and advanced techniques such as pinging multiple hosts simultaneously or using different protocols for diagnostics. Key metrics like time, packet loss, and round trip times are explained, along with steps for resolving issues related to slow responses or unreachable destinations. The article emphasizes the importance of `ping` in diagnosing network problems and enhancing connectivity troubleshooting skills.

How to Ping a Server Using Ping on the Terminal in Ubuntu

<div>

<p>This is an article about how to use the command-line tool <code>whois</code> to query database servers for domain registration and technical details in Linux operating systems, specifically focusing on Ubuntu. In this article you will find information about setting up your terminal environment, installing necessary tools, and executing basic and advanced queries using the <code>whois</code> command. Additionally, we’ll explore how to interpret results effectively and understand common WHOIS database entries.</p>
<h2>Introduction to WHOIS and Its Importance</h2>
<p>The WHOIS protocol is a directory service that allows users to query databases for information about Internet resources, primarily domain names, IP addresses, and other related details managed by the Internet Corporation for Assigned Names and Numbers (ICANN) or specific Regional Internet Registries (RIRs). This tool is invaluable for network administrators, security researchers, and anyone interested in understanding the ownership and management of internet infrastructure. Using <code>whois</code> from your terminal can provide insights into domain registration details, contact information, IP address assignments, and more.</p>
<h2>Setting Up Your Terminal Environment</h2>
<p>Before diving into WHOIS queries, ensure you are working on an Ubuntu system with a basic understanding of using the command line. If you’re new to Linux terminals or have not used them extensively in Ubuntu, it might be helpful to familiarize yourself with some basics:</p>
<ol>
<li><strong>Opening Terminal</strong>: Use <code>Ctrl+Alt+T</code> on your keyboard to open the terminal window quickly.</li>
<li><strong>Navigating Directories</strong>: Learn commands such as <code>cd</code>, <code>ls</code>, and <code>pwd</code>.</li>
<li><strong>Managing Files</strong>: Know how to use <code>cp</code>, <code>mv</code>, <code>rm</code>, and other file manipulation commands.</li>
</ol>
<p>Once you’re comfortable with these basics, we can proceed to set up your environment for WHOIS queries.</p>
<h2>Installing the WHOIS Command Line Tool</h2>
<p>The <code>whois</code> tool is not included by default in all Ubuntu installations. To install it, open your terminal and execute:</p>
<pre><code class="language-bash">sudo apt-get update
sudo apt-get install whois -y
</code></pre>
<p>This command updates your package lists from their repositories and installs the <code>whois</code> utility.</p>
<h2>Basic WHOIS Queries</h2>
<p>With <code>whois</code> installed, you can start querying domain names or IP addresses for information. Here are some basic queries:</p>
<h3>Querying a Domain Name</h3>
<p>To get registration details of a specific domain name like example.com, type:</p>
<pre><code class="language-bash">whois example.com
</code></pre>
<p>This command fetches detailed information about the specified domain from ICANN’s WHOIS database.</p>
<h3>Querying an IP Address</h3>
<p>For IPv4 addresses:</p>
<pre><code class="language-bash">whois 192.0.2.1
</code></pre>
<p>And for IPv6 addresses:</p>
<pre><code class="language-bash">whois 2001:db8::1
</code></pre>
<p>These queries return information about the ownership and allocation of the respective IP address.</p>
<h2>Advanced WHOIS Query Techniques</h2>
<p>Beyond basic queries, <code>whois</code> offers several options to customize your searches. Here are some advanced techniques:</p>
<h3>Specifying a Specific Field</h3>
<p>You can request specific fields from the output by using <code>-h</code> for specifying the field or server, though commonly you’ll use flags like <code>-s</code> and <code>-i</code>. For example, if you’re only interested in expiration dates of domains:</p>
<pre><code class="language-bash">whois -oX whois.nic.ar example.com | grep "EXPIRED"
</code></pre>
<h3>Querying Different WHOIS Servers</h3>
<p>Not all domain names are registered through ICANN’s servers. Some top-level domains (TLDs) use their own registrars, which have separate WHOIS databases:</p>
<pre><code class="language-bash">whois -h whois.nic.it example.com
</code></pre>
<p>This command queries the <code>.it</code> TLD database for information about <code>example.com</code>.</p>
<h3>Limiting Output</h3>
<p>For large outputs, you can limit the display to the first few lines or filter specific parts using tools like <code>head</code>, <code>tail</code>, and <code>grep</code>. For instance:</p>
<pre><code class="language-bash">whois example.com | head -n 20
</code></pre>
<p>This command shows only the first 20 lines of the WHOIS query result.</p>
<h2>Interpreting WHOIS Query Results</h2>
<p>Understanding what each piece of information means is crucial. Typical fields include:</p>
<ul>
<li><strong>Registrant</strong>: The entity that owns the domain.</li>
<li><strong>Registrar</strong>: The company through which the registration was processed.</li>
<li><strong>Creation Date</strong>: When the domain was registered.</li>
<li><strong>Expiration Date</strong>: Until when the domain remains valid without renewal.</li>
<li><strong>Name Servers (NS)</strong>: DNS servers used to manage the domain.</li>
</ul>
<h2>Common Challenges and Solutions</h2>
<h3>Dealing with Privacy Protection Services</h3>
<p>Many registrars offer privacy protection services which mask personal information from public WHOIS records. In such cases, you’ll see placeholder data or a notice indicating that contact details are available only upon request:</p>
<pre><code class="language-bash"># Example output where whois data is protected by a service like DomainsByProxy
whois example.com | grep "Registrant"
</code></pre>
<h3>Handling Rate Limits and Blocked Access</h3>
<p>Some servers impose limits on the number of queries from a single IP address within a given timeframe to prevent abuse. If you encounter rate limit errors, consider using proxy services or reducing your query frequency.</p>
<h2>Conclusion</h2>
<p>Using the <code>whois</code> command line tool in Ubuntu allows for efficient querying of domain registration information and technical details related to internet resources. By mastering basic commands, exploring advanced features like specifying fields and custom WHOIS servers, and understanding how to interpret results, you can make full use of this powerful directory service.</p>
<p>Read this article to find out about the essential steps needed to set up your Ubuntu terminal for effective WHOIS queries, ensuring you have everything required to start investigating domains or IP addresses. Whether you’re a network administrator, security researcher, or just curious about internet infrastructure, <code>whois</code> is an indispensable tool in your arsenal.</p>
<hr>
<p>This guide provides a comprehensive introduction and tutorial on using the <code>whois</code> command in Ubuntu for both beginners and those looking to enhance their knowledge of WHOIS database queries.</p>

</div>

This article outlines how to use the `whois` command-line tool in Ubuntu to query domain registration and technical details from WHOIS databases. It covers setting up your terminal environment, installing necessary tools, performing basic and advanced queries, interpreting results, and troubleshooting common issues such as rate limits and privacy protection services. Key sections include an introduction to WHOIS, installing the `whois` utility, executing queries for domains and IP addresses, specifying fields and custom servers, managing output size, and understanding typical result fields like registrant information and expiration dates. The guide aims to equip users with essential skills for efficient use of `whois`, making it a valuable tool for network administrators, security researchers, and anyone interested in internet infrastructure details.

How to Query WHOIS Database Servers Using whois on Ubuntu Terminal

<div>

<p>This is an article about how to use the <code>dig</code> command, a powerful utility for querying the Domain Name System (DNS) from the terminal in Ubuntu. In this article you will find information about what the <code>dig</code> tool is and why it’s essential for network administrators and developers who work with DNS records.</p>
<h2>Introduction</h2>
<p>Understanding and managing DNS entries can be crucial when configuring domain names, setting up websites, or troubleshooting connectivity issues on your local network or across the internet. The <code>dig</code> command, which stands for “Domain Information Groper,” is a powerful tool that allows you to perform various types of DNS queries. This article will guide you through using <code>dig</code> in Ubuntu, offering insights into its features and providing practical examples.</p>
<h2>What is DNS?</h2>
<p>Before diving into how to use <code>dig</code>, it’s important to understand what DNS (Domain Name System) is. DNS translates human-readable domain names like “www.example.com” into IP addresses that computers can interpret and connect to. It acts as a distributed database where records are stored, and every domain has an associated set of such records.</p>
<h2>What is <code>dig</code>?</h2>
<p>The <code>dig</code> utility in Ubuntu is a flexible command-line tool for querying DNS servers directly. Unlike using a web interface or other tools with limited features, <code>dig</code> offers comprehensive control over the types of queries you can make and the information returned by DNS servers. This makes it invaluable for network administrators who need to diagnose issues, test configurations, or understand how their domain names are resolving.</p>
<h2>Installing <code>dig</code></h2>
<p>To use <code>dig</code>, you first need to ensure that it’s installed on your Ubuntu system. The <code>dig</code> command is part of the <code>dnsutils</code> package which can be easily installed using apt-get:</p>
<pre><code class="language-bash">sudo apt-get update
sudo apt-get install dnsutils
</code></pre>
<p>Once installed, you should have access to the <code>dig</code> utility.</p>
<h2>Basic Usage</h2>
<p>The simplest way to use <code>dig</code> is with just a domain name. For example:</p>
<pre><code class="language-bash">dig example.com
</code></pre>
<p>This command queries DNS records for “example.com” and returns all available information in a standard format:</p>
<ul>
<li><strong>Query</strong>: The query type, often “IN” (Internet) by default.</li>
<li><strong>NAME</strong>: The domain name you queried.</li>
<li><strong>CLASS</strong>: Usually “IN.”</li>
<li><strong>TYPE</strong>: Type of record returned. Common types include A, AAAA, MX, TXT, etc.</li>
<li><strong>TTL</strong>: Time to live in seconds before the data expires and must be refreshed.</li>
</ul>
<p>For a more detailed output, you can specify different query types:</p>
<pre><code class="language-bash">dig example.com MX  # Query for Mail Exchange records
</code></pre>
<h2>Advanced Queries</h2>
<h3>Specifying Nameservers</h3>
<p>By default, <code>dig</code> uses your system’s DNS settings to determine which nameserver to use. However, you might want to test specific servers directly.</p>
<p>To do this:</p>
<pre><code class="language-bash">dig @8.8.8.8 example.com  # Use Google Public DNS server
</code></pre>
<h3>Filtering Output with +short</h3>
<p>If you just need a quick lookup without the full verbose output, <code>+short</code> can be used:</p>
<pre><code class="language-bash">dig +short example.com A  # Get only IP addresses (A records)
</code></pre>
<p>This is particularly useful for scripting or quickly checking if a domain resolves to an expected address.</p>
<h3>Querying Specific Types of Records</h3>
<p>You’re not limited to just MX and A types. You can query any type supported by DNS:</p>
<pre><code class="language-bash">dig example.com TXT  # Get TXT records that often contain SPF and DKIM information.
</code></pre>
<h2>Troubleshooting with <code>dig</code></h2>
<p>If you suspect issues with your DNS configuration or if a domain isn’t resolving properly, <code>dig</code> offers several ways to diagnose problems.</p>
<h3>Checking TTLs</h3>
<p>A high or low TTL can affect how changes propagate across the internet:</p>
<pre><code class="language-bash">dig +nocomments +nocmd example.com NS  # Query Name Servers and omit comments for clarity.
</code></pre>
<h3>Analyzing DNS Propagation</h3>
<p>After making a change, use <code>dig</code> to monitor when it propagates globally. This is especially useful with services like Cloudflare or other CDN providers.</p>
<pre><code class="language-bash">while true; do dig +short example.com A | grep -v "^$"; sleep 60; done
</code></pre>
<p>This command will continuously ping the domain and output any changes in IP addresses, helping you track when DNS records update across different servers worldwide.</p>
<h2>Conclusion</h2>
<p>This article provided an overview of how to use <code>dig</code> for looking up DNS entries on Ubuntu. Whether you’re setting up a new website, diagnosing issues with your current configuration, or simply learning more about DNS management, the <code>dig</code> utility offers unparalleled flexibility and control over querying DNS records.</p>
<p>By mastering commands like those covered in this article, network administrators can gain deeper insights into their systems’ performance and ensure smooth operation of services that rely heavily on DNS.</p>

</div>

This article explains how to use the `dig` command in Ubuntu, a powerful tool for querying DNS entries from the terminal. It covers the basics of DNS, introduces `dig`, guides users through installing it via `dnsutils`, and demonstrates its usage with various examples, such as basic queries, specifying nameservers, filtering output, and troubleshooting issues like TTL checks and DNS propagation monitoring. By mastering `dig`, network administrators can effectively manage domain configurations and diagnose connectivity problems.

Network

How to Monitor Network Bandwidth Using Nload on the Terminal in Ubuntu

How to Ping a Server Using Ping on the Terminal in Ubuntu

How to Query WHOIS Database Servers Using whois on Ubuntu Terminal

How to Look Up DNS Entries Using dig on the Terminal in Ubuntu