Purpose of this article

** Understand the "temporary" part of UNIX and Linux. ** **

The reason I decided to summarize this was an error during the environment construction work. It was because I put in code to write different Linux distributions when I was tweaking the config file to customize the display of the terminal. It seems.

... what is a Linux distribution? In the first place, I only know that Linux is an OS ...!

When I was researching, various words came out and I was almost confused, so I personally summarized the part "I wonder if I should understand this much for the time being?"

What is Linux

--OS developed in 1991 -** Open source software that can be freely modified and distributed ** --Since it was developed by Linus Torvalds with reference to UNIX, "Linux" --Compared to other OS, it has the feature that it works lightly even on a low-performance computer. ――It is widely used in personal computers, smartphones, and servers. --Amazon AWS Amazon Linux, Rasberry Pi Raspbian, Android are Linux-based OS

...that? By the way, even though I don't remember installing Linux myself, I use cd and ls listed in the "Linux Command Collection". why?

It seems that the miso is that "Linux was made with reference to UNIX". Let's examine the features of UNIX as well.

What is UNIX?

--OS developed in 1969 -** Developed by a company and paid for, intellectual property rights belong to the company ** ――It is often used as an OS for large computers and network servers that are highly stable and need to run for a long time. -** macOS is based on BSD UNIX **

I see, ** macOS is based on UNIX, so the commands are almost the same **.

However, it seems that ** options are often written and have different meanings **, so it seems better to check whether they are UNIX commands or Linux commands, especially when referring to commands with options.

If you say "It's inconvenient for the reference materials to use Linux commands ..." on macOS, you can use the basic Linux commands with the UNIX-based OS by including the package ** GNU coreutils **. It seems like this. (Convenient!) This article seems to be helpful for the introduction method. Procedure for installing standard commands for text processing on macOS

Also, "BSD series" seems to be an OS developed based on BSD (Berkeley Software Distribution), among UNIX-based OSs.

The word "Linux" is used in two ways

Linux in a narrow sense: Linux kernel
Linux in a broad sense: Linux distribution

Strictly speaking, it seems to refer to the "Linux kernel".

What is the Linux kernel?

** The core of OS functionality **. An important part that plays the role of connecting hardware such as CPU and keyboard with applications such as Finder and Safari.

What is a Linux distribution?

The LPI-JAPAN article explains:

A Linux distribution is a collection of various programs such as the Linux kernel and user interface that can be used immediately by users as an OS.

In other words, a Linux distribution is a ** package that distributes the Linux kernel and applications and tools together **.

Linux distribution school

Since Linux is open source, it is said that it will be divided into three schools as a result of various companies modifying it.

--Red Hat system --Distribution developed by Red Hat --There is a paid RHEL (Red Hat Enterprise Linux) and a free OS for its clone. --Debian --Open source distribution --User friendly --Slackware system --Distribution featuring safety, security and speed ――The officially distributed state is one completed form, and it is said that it is relatively difficult because it depends on the user's judgment and operation when customizing and using it such as adding software.

Specific Linux distribution example

--Red Hat system - RedHatEnterpriseLinux ――For a fee, you can receive technical support and long-term and accurate security fixes. - CentOS --RedHatLinux with the paid part removed --One of the major operating systems used by companies - Fedora --Working on the latest technology --Debian - Debian --Origin of Ubuntu --One of the major operating systems used by companies - Ubuntu --Use as soon as you install --A wealth of information, for beginners --One of the major operating systems used by companies - Linux mint --Derived from Ubuntu --Easy to use without the need for difficult settings --It also comes with an Office application that has functions similar to Microsoft Office. - elementaryOS --Derived from Ubuntu - ZorinOS --Derived from Ubuntu --Slackware system - Slackware --Long-established store --Basic knowledge required for Unix / Linux operation management is required to master it.

Detour: What is GNU / Linux?

When I was researching, I often saw the notation "GNU / Linux". What is this? Quote from wikipedia ..

The GNU / Linux system (or the GNU / Linux operating system, or GNU / Linux for short), commonly referred to as "Linux", uses a lot of software from the GNU Project, such as glibc and bash. Important libraries and software are the names claimed by the GNU Project as the names that are being developed by GNU.

wikipedia has ["GNU / Linux Name Controversy"](https://ja.wikipedia.org/wiki/GNU/Linux%E5%90%8D%E7%A7%B0%E8%AB%96%E4%BA There is a page like% 89), but I wondered if I should think that ** a Linux distribution that contains a lot of software developed by the GNU Project is sometimes called GNU / Linux **.

Summary: UNIX is a senior OS of Linux

--Linux is based on UNIX --The big difference between UNIX and Linux is "whether the intellectual property rights belong to the development company for a fee, or can it be modified or distributed free of charge in open source?" --Many of the commands are the same on UNIX and Linux, but the meanings of the options may differ. --By introducing a package called GNU coreutils, you can use Linux commands even on UNIX-like OS. ――Linux has two meanings, "Linux kernel" which is the basis of OS and "Linux distribution" which is integrated with applications.

Reference site

-OS in the world-"MS-DOS" that built an era that supports computers -Differences between Unix and Linux that can be explained to people in 3 minutes -[Rough summary] Compare Linux distributions -Weblio dictionary: BSD OS -Is there any Linux that does not correspond to GNU / Linux?

Understand the "temporary" part of UNIX / Linux