It's a Mac. What is the Linux command Linux?

What is Linux? I did a deep digging because I didn't understand, so I will record it.

First of all, my question when I started programming as a Mac user is ** Is Linux knowledge of Windows? ** ** It starts from what I thought.

** Conclusion. Windows doesn't matter. Mac is Unix-like. However, Linux and Unix have almost the same commands, but they are compatible even if they are different. ** **

** Supporting the conclusion. ** ** Considering the birth of Linux, it is easy to realize that the number of types has increased, so please see below. ↓　↓　↓　↓　↓　↓　↓　↓　↓　↓　↓　↓　↓　↓　↓　↓　↓　↓　↓　↓　↓　↓　↓　↓　↓

** 1. The birth of Unix (Linux is based on Unix) ** UNIX was born in the 1960s at Bell Labs, an American telecommunications company, AT & T. At that time, Bell Labs was participating in the development of an OS called MULTICS as a previous research. Meanwhile, researcher Ken Thompson discovered a computer that was not used in a corner of the laboratory, and in order to test-operate the mechanism that he thought of, he installed some programs that are the basic elements of the OS on the computer. It was installed. This is said to be the beginning of UNIX.

** 2. Various separations and combinations ** The distributed UNIX was freely modified by the maintainers. As a result, UNIX was created by various organizations and companies, and it became less cohesive as UNIX. To solve this problem, AT & T officially started a licensing agreement to manage UNIX. This AT & T UNIX is called System V, and since then, only organizations that have a contract with AT & T (and the UNIX license management body) can declare their OS as UNIX. On the other hand, some organizations do not have a license agreement with AT & T. UNIX developed by these organizations is called a UNIX compatible OS.

** 3. Derived UNIX ** In this way, a great many UNIXs, including compatible OSs, have become widespread. The Berkeley version of UNIX had a major impact on its derivation. The Berkeley version of UNIX is a derivative operating system created by UNIX developer Ken Thompson when he was at the University of California, Berkeley. The biggest feature of this derivative OS is that IP (Internet Protocol), which was adopted as a communication method inside the US military at that time, was implemented. This is why UNIX is said to be strong on the Internet. This Berkeley version of UNIX is called BSD (Berkeley Software Distribution) and has formed two streams alongside System V.

** 4. The birth of Linux ** Many UNIXes continued to be used by companies and universities under high license fees. It was a dream of many users to be able to use it at home and on a personal computer.

Meanwhile, a post saying "I'm making an OS (similar to UNIX) now" was posted online in 1991. The contributor was Linus Torvalds, a Finnish university student at the time, who apparently started writing such programs by learning computer functions. The program has been published on the network.

The prototype of the program was very primitive and could only be run by someone familiar with computers. The basic design was similar to UNIX, but it was a unique UNIX-compatible OS that had neither System V flow nor BSD flow. After that, the small program Linus Torvalds created for learning combined with further enhancements, software, and tools to work well as a UNIX-compatible operating system.

Yes, Linux was born.

The most distinctive feature of Linux programs was their license format. Linux programs use a license format called the GPL (GNU General Public License). The GPL was created by Richard Stallman of the GNU Project. It is one of the free software licenses including the following features.

Freedom to run the program Freedom to modify the source Freedom to use and redistribute Right to release an improved program

Linux was developed by many distributors and is now used by a large number of users. This is because Linux has adopted the GPL, which is a license system that can be used and modified virtually free of charge. Due to the nature of the license, GPL, which realizes free software, attaches the source code or offers to provide the source code when distributing software based on the software received under the GPL to the general public in binary format. You must meet the condition of doing.

However, as a result of this licensing system working well, Linux has become a style in which all users benefit from it and develop it without being monopolized by some individuals or organizations. Linux is now open to the public by various distributors, and it may be because Linux has adopted the GPL that makes it easy to install Linux on personal computers.

Excerpt :: “Linux Standard Textbook”. Apple Books

Distribution

Linux has been improved day by day, and what initially had only a single function was improved to run on various hardware, and gradually became a UNIX-compatible OS.

However, the initial Linux was very difficult to install and was only available to highly skilled users of some computers. Therefore, various organizations have put together the programs necessary to use Linux and made it easy to install with simple steps. This is the beginning of the Linux distribution. An organization that develops Linux distributions in this way is called a distributor.

Representative Linux distributors include Red Hat, the Debian Project, and Canonical, which develops Ubuntu, and various organizations continue to release "Linux."

Excerpt :: “Linux Standard Textbook”. Apple Books

As a classification, it looks like this.

Well, thank you for reading this far. The quoted material is a teaching material that you can learn Linux commands made for qualification. If you register as a member, you can download it for free, and it has a good reputation for good quality, so I will post a link. Linux standard textbook https://linuc.org/textbooks/linux/form.php

Articles that I used as a reference https://tech-camp.in/note/technology/14821/ https://eng-entrance.com/unix_linux https://qiita.com/kanaya/items/15ef1ba8af83a6b5c2c9