Linux Fundamental

Role The first decision when specifying any computer system is the machine’s role. Will you be sitting at the console running productivity applications or web browsing? If so, a familiar  desktop  is best. Will the machine be accessed remotely by many users or provide services to remote users? Then it’s a  server . Servers typically sit in a rack and share a keyboard and monitor with many other computers, since console access is generally only used for configuration and troubleshooting. Servers generally run as a CLI, which frees up resources for the real purpose of the computer: serving information to clients (any user or system that accesses resources remotely). Desktop systems primarily run a GUI for the ease of use of their users. Function Next, determine the functions of the machine. Is there specific software it needs to run, or specific functions it needs to perform? Will there be hundreds, even thousands, of these machines running at the same time? What is...

An  operating system  is software that runs on a computing device and manages the hardware and software components that make up a functional computing system. Modern operating systems don’t just manage hardware and software resources, they schedule programs to run in a multi-tasking manner (sharing the processor so that multiple tasks can occur apparently simultaneously), provide standard services that allow users and programs to request something happen (for example a print job) from the operating system, and provided it’s properly requested, the operating system will accept the request and perform the function needed. Desktop and server operating systems are by nature more complex than an operating system that runs on a single-purpose device such as a firewall, or a mobile phone. From a simple set-top box that provides a menu interface for a cable provider, to supercomputers and massive, parallel computing clusters, the generic term  operating system  is used t...

There are two basic types of interfaces available that allow you to interact with the operating system. The typical computer user today is most familiar with a  graphical user interface (GUI) . In a GUI, applications present themselves in windows that can be resized and moved around. There are menus and tools to help users navigate. Graphical applications include web browsers, graphics editing tools and email, to name a few. Below is an example of a graphical desktop, with a menu bar of popular applications to the left, a LibreOffice document being edited in the foreground and a web browser in the background. The second type of interface is the  command line interface (CLI) , a text-based interface to the computer. The CLI relies primarily on keyboard input. Everything the user wants the computer to do is relayed by typing commands rather than clicking on icons. It can be said that when a user clicks on an icon, the computer is telling the user what to do, but, when the ...

People that say their computer runs Linux usually refer to the kernel, tools, and suite of applications that come bundled together in what is referred to as a  distribution . Take Linux and the GNU tools, add some user-facing applications like a web browser and an email client, and you have a full Linux system. Individuals and even companies started bundling all this software into distributions almost as soon as Linux became usable. The distribution includes tools that take care of setting up the storage, installing the kernel, and installing the rest of the software. The full-featured distributions also include tools to manage the system and a  package manager  to help you add and remove software after the installation is complete. Like UNIX, there are distributions suited to every imaginable purpose. There are distributions that focus on running servers, desktops, or even industry-specific tools such as electronics design or statistical computing. The major players ...

Historically, most software has been issued under a closed-source license, meaning that you get the right to use the machine code, but cannot see the source code. Often the license explicitly says that you may not attempt to reverse engineer the machine code back to source code to figure out what it does! The development of Linux closely parallels the rise of  open source software . Open source takes a source-centric view of software. The open source philosophy is that you have a right to obtain the software source code and to modify it for your own use. Linux adopted this philosophy to great success. Linus made the source programming code (the instructions a computer uses to operate) freely available, allowing others to join in and shape this fledgling operating system. It was not the first system to be developed by a volunteer group, but since it was built from scratch, early adopters could influence the project’s direction. People took the source, made changes, and shared th...

The definition of the word Linux depends on the context in which it is used. Linux means the  kernel  of the system, which is the central controller of everything that happens on the computer. When most people refer to Linux, they are really referring to a combination of software called  GNU/Linux , which defines the  operating system .  GNU  is the  free software  that provides open source equivalents of many common UNIX commands. The  Linux  part of this combination is the  Linux kernel , which is the core of the operating system. The kernel is loaded at boot time and stays running to manage every aspect of the functioning system. The story of Linux begins with  UNIX , an operating system developed at AT&T Bell Labs in the 1970s. UNIX is written in the  C  language making it uniquely portable amongst competing operating systems, which were typically closely tied to the hardware for which they were written. I...

  Linux is Everywhere Hello and welcome to  Information Technology HelpDesk Online ! Linux is everywhere; Linux jobs are everywhere. There is a demand for Linux skills in just about every industry and job category on the planet, and not enough Linux talent to meet this growing demand. It’s also fun and rewarding to work with something that’s so much a part of our modern lives yet which so few people understand. If someone says they have Linux experience, it might refer to configuring systems, running web servers, or any number of other services and programs that operate on top of Linux. Over time, Linux administration has evolved to encompass just about every task that a modern business, educational institution, or government organization might use in their daily operations. The journey of learning you are beginning today has no ending point. It can take you in a myriad of different directions, from cybersecurity to application and game development, system administrati...