Linux Fundamentals

Lesson 1: Introduction to Linux

Overview

Linux is a powerful and popular open-source operating system that is widely used in the tech industry. Developed in the early 1990s by Linus Torvalds, Linux has since grown into a versatile platform that powers everything from personal computers and servers to mobile devices and embedded systems.

Key Concepts

• Open-Source: Linux is open-source, meaning that its source code is freely available to the public. This allows users to modify and distribute the operating system according to their needs.

• Kernel: The Linux kernel is the core component of the operating system that manages hardware resources and provides essential services to applications.

• Distributions: There are many different distributions, or "distros," of Linux, each with its own set of features and software packages. Some popular distros include Ubuntu, Fedora, and Debian.

Examples

• Ubuntu: A user-friendly Linux distribution known for its ease of use and extensive software repositories.

• CentOS: A stable and secure Linux distribution often used for server environments.

• Raspberry Pi OS: A lightweight Linux distribution designed for the Raspberry Pi single-board computer.

Benefits of Linux

1. Cost-effective: Linux is free to use and distribute, making it a cost-effective choice for individuals and organizations.

2. Customizability: Users can customize Linux to suit their needs, whether it's for personal use or for specialized applications.

3. Security: Linux is known for its security features, such as user permissions and access control, making it a popular choice for servers and critical systems.

Conclusion

Linux is a versatile and powerful operating system that offers a wide range of benefits to users. Understanding the fundamentals of Linux is essential for anyone looking to work in the tech industry or simply expand their knowledge of computer systems.

Who is Red Hat?

Red Hat is the world's leading provider of open source software solutions, by using a community-powered approach to reliable and high-performance cloud, Linux, middleware, storage, and virtualization technologies. The mission of Red Hat is to be the catalyst in communities of customers, contributors, and partners to create better technology the open source way.

The role of Red Hat is to help customers to connect with the open source community and their partners to effectively use open source software solutions. Red Hat actively participates in and supports the open source community. Many years of experience have convinced the company of the importance of open source to the future of the IT industry.

Red Hat is best known for its participation in the Linux community and the Red Hat Enterprise Linux distribution. Red Hat is also active in other open source communities, including middleware projects that are centered on the JBoss developer community. Red Hat also provides virtualization solutions, cloud technologies such as OpenStack and OpenShift, and the Ceph and Gluster software-based storage projects, plus others.

The ecosystem:

Red Hat Enterprise Linux (RHEL) is Red Hat's commercial production-grade Linux distribution. Red Hat develops and integrates open source software into RHEL through a multistage process.

• Red Hat participates in supporting individual open source projects. It contributes code, developer time, resources, and support, and often collaborates with developers from other Linux distributions, to improve the general quality of software for everyone.

• Red Hat sponsors and integrates open source projects into the community-driven Fedora distribution. Fedora provides a free working environment to serve as a development lab and proving ground for features to be incorporated into CentOS Stream and RHEL products.

• Red Hat stabilizes the CentOS Stream software to be ready for long-term support and standardization, and integrates it into RHEL, the production-ready distribution.

The Red Hat Enterprise Linux Ecosystem

Red Hat Enterprise Linux

Red Hat Enterprise Linux (RHEL) is Red Hat's production-ready, commercially supported Linux distribution. In the computing industry, RHEL is acknowledged as the leading platform for open source computing. RHEL is extensively tested and has a worldwide ecosystem of support partners for hardware and software certifications, consulting services, training, and multi-year support and maintenance guarantees.

Red Hat builds RHEL major releases directly from the CentOS Stream continuous development project, which is sourced from Fedora. In contrast to the previous RHEL development model, the releases were constructed internally with less transparency, and the source was provided only for building as CentOS Linux after the RHEL release. Now the new CentOS Stream development model is open and available to all, for feedback and contribution, and the code is prepared to be the next major RHEL release.

RHEL uses a subscription-based support model, and does not charge license fees for open-source software. Red Hat support subscriptions provide product support, maintenance, updates, security patches, and access to the Customer Portal Knowledgebase, utilities, and downloadable releases of Red Hat products.

Red Hat Enterprise Linux Continuous Development

As packages are updated, they are then pushed into CentOS Stream and the nightly build of RHEL.

Why Should You Learn about Linux?

Linux is a critical technology for IT professionals to understand.

Linux is in widespread use, worldwide. Internet users interact with Linux applications and web server systems daily, by browsing the World Wide Web and using e-commerce sites to buy and sell products.

Linux is in use for much more than the internet. Linux manages point-of-sale systems and the world's stock markets, powers smart TVs and in-flight entertainment systems, and runs most of the top 500 supercomputers in the world. Linux provides the core technologies that power the cloud revolution and the tools to build the latest generations of container-based microservices applications, software-based storage technologies, and big data solutions.

In the modern data center, Linux and Microsoft Windows are the predominant operating systems. Linux use continues to expand in enterprise, cloud, and device spaces. Due to its widespread adoption, you have many reasons to learn Linux:

• A Windows user needs to interoperate with Linux systems and applications.

• In application development, Linux commonly hosts the application and its runtime.

• In cloud computing, both private and public cloud instances use Linux as the operating system.

• Mobile applications and Internet of Things (IoT) devices commonly run on Linux.

• When looking for new IT career opportunities, Linux skills are in high demand.

What Makes Linux Great?

If someone asks you "What makes Linux great?", then you have many answers to pick from:

• Linux is open source software.

  Being open source means that you can see all of how a program or system works. You can also experiment with changes and share them freely for others to use. The open source model means that improvements are easier to make, enabling faster innovation.

• Linux provides a command-line interface (CLI) for easy access and powerful scripting.

  Linux is built around a basic design philosophy that users can perform all administration tasks from the CLI. It enables easier automation, deployment, and provisioning, and simplifies both local and remote system administration. Unlike many other operating systems, these capabilities were in the architecture from the start, and result in ease of use and stability.

• Linux is a modular operating system that is designed to easily replace or remove components.

  System components can be upgraded and updated when needed. A Linux system can be a general-purpose development workstation or a purposefully minimized software appliance.

What Is Open Source Software?

Open source software is software with source code that anyone can use, study, modify, and share.

Source code is the set of human-readable instructions that are used to make a program. Code might be in interpretive form, such as a script, or compiled into a binary executable that the computer runs directly. Source code becomes copyrighted when created, and the copyright holder controls the terms under which the software can be copied, adapted, and distributed. Users can use the software according to its software license.

Some software uses "proprietary" or "closed source" source code that only the originating person, team, or organization can see, or change, or distribute. Proprietary licenses typically restrict the user to running the program, and provide limited or no access to the source.

Open source software is different. When a copyright holder provides software under an open source license, they grant the user the right to run the program and to view, modify, compile, and redistribute the source to others, royalty-free. Open source licensing promotes collaboration, sharing, transparency, and rapid innovation, because it encourages more people to modify and improve the software and to share enhancements more widely.

Open source software can still be provided for commercial use. Open source is a critical part of many organizations' commercial operations. Some open source licenses allow code to be reused in proprietary products. Anyone can sell open source code, but open source licensing generally allows the customer to redistribute the source code. Open source vendors such as Red Hat provide commercial support for deploying, managing, and building solutions that are based on open source products.

Open source has many benefits for the user:

• Control: See what the code does and improve it.

• Training: Learn from real-world code and develop more applications that are useful.

• Security: Inspect sensitive code, and fix it even without the original developers' help.

• Stability: Rely on code that can survive the loss of the original developer.

What Is a Linux Distribution?

A Linux distribution is an installable operating system that is constructed from a Linux kernel and that supports user programs and libraries. A complete Linux system is developed by multiple independent development communities that work cooperatively on individual components. A distribution provides an easy method to install and manage a working Linux system.

In 1991, graduate student Linus Torvalds developed a UNIX-like kernel that he named Linux, and licensed it as open source software under the GPL. The kernel is the core of the operating system and manages hardware, memory, and the scheduling of running programs. The Linux kernel is supplemented with other open source software, including utilities and programs from the GNU Project, a graphical interface from MIT's X Window System. The Linux kernel also includes other open source components, such as the Sendmail mail server and the Apache HTTP web server, to become a complete open source UNIX-like operating system.

A major challenge for Linux users is to assemble all these software pieces from many sources. Early Linux developers provided a distribution of prebuilt and tested tools that users could download and install to quickly implement Linux systems.

Many Linux distributions exist, each with differing goals and support criteria. Generally, distributions have some common characteristics:

• Distributions consist of a Linux kernel and support user-space programs.

• Distributions can be small and single-purpose, or can include thousands of open source programs.

• Distributions provide a means to install and update the software and its components.

• The distribution provider supports the software, and ideally, participates in the development community.