1. What is Linux?

(Jan. 10, 2022)

• Linux is a computer operating system. When installed on suitable computer hardware, it provides an environment for running software applications.
• Linux is an independent implementation of a Unix-style system, compliant with POSIX standards. It was developed from scratch, and does not incorporate code from commercial Unix platforms.
• Linux is developed by thousands of developers who either donate their time or are paid by companies to contribute to the system that they use in their business. No single person or entity “owns” Linux. Instead, it belongs to the individual copyright holders of the many programs that make up a Linux system.
• “Linux” is a portmanteau of its developer's name – Linus Torvalds – and “Unix”. (Linus lives amongst us here in Portland, OR).
• Linux surely is the most-used operating system in existence. It is running on everything from smart watches to laptops to mainframes to supercomputers (the 500 most powerful computers in the world operate on Linux). Most of the servers that comprise the Internet run Linux. The Linux kernel is the basis for Android, running on untold millions of smartphones and tablets.

• Linux systems are modular. They consist of many independent components that work together through standard interfaces – the POSIX standards. As a result, a Linux system administrator can choose from numerous alternatives at every level. Contrast that to Windows, which is monolithic.
• Install only what you need. Linux won't force you to install software you don't need. For example, if you want to run a server-based application, such as a Web server or a wiki, you don't need a graphical interface. With Linux, you don't have to install one. In fact, many Linux servers run “headless”, with no keyboard or monitor, being controlled remotely via SSH.
• Networking is native to Linux, built in as part of its design. The internet is really nothing more than a gigantic Unix network. The basic protocols and technology that make it work were created to connect Unix-based systems together, and are implemented natively in Linux.

• A Linux system consists of Free and Open Source Software (FOSS). That means it is licensed to the user under terms that allow it to be used and modified as desired.
• In addition to being free as in “freedom”, most software in the Linux world also is free as in “beer”. There is no prohibition to charge for the software, but most for-profit vendors charge instead for providing direct support. That makes the software free to use, while letting people earn a living by supporting it.

That's a quick summary of what Linux is about. In future inside looks, we'll talk in greater detail about many of the things I've mentioned today.

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