Linux rookie takeoff Road "two" Linux basic knowledge

basic knowledge of Unix operating system1. What is UNIX?

UNIX is a computer operating system, which is a control program used to coordinate, manage and control computer hardware and software resources.

What are the features of the 2.Unix operating system?

Multi-user and multi-tasking. Multiple users indicate that multiple users can use the UNIX operating system at the same time and do not interfere with each other; multitasking means that any user can perform multiple tasks on UNIX at the same moment.

3.Unix Brief History before and after birth

1946: The world's first computer, ENIAC, was born at the University of Pennsylvania in the United States, with the aim of calculating artillery shells and weighing up to 30 tonnes.

1947: Bell Lab invented the transistor.

1958: Ti invented integrated circuits.

Before 1969, Bell Labs, MIT, GE jointly developed Multics.

1969: Ken Thompson of Bell developed UNICs for himself (this is called informal name, because thought originates from Multics).

1971: Intel releases the first microprocessor 4004.

1973: Unix was formally born, Bell Lab's Dennis developed C language, and C language rewrite UNICs, formally named UNIX.

1977: Unix Branch--bsd was born, University of California, Berkeley Bill Joy Gets the UNIX source code, modifies and perfects it to become an important branch of Unix Bsd-unix. After the x86 on the FreeBSD is the BSD revision.

1979: AT/T announces the resumption of UNIX copyrights, no longer open, and the release of UNIX System V architecture. UNIX systems have emerged in many companies over the years.

1979: Intel launches 8086/8088 CPU.

1981: IBM's PC launch of IBM Pc,x86 architecture became popular.

1984: The Minix operating system of the x86 architecture was born.

1984: Stallman launches the GNU project with the aim of opening up a free, open source Unix. Because of the vast project, Stallman decided to write the application first, such as Gcc,emacs.

1988: XFree86 was born, that is, the x86 version of Unix on the GUI system.

1991: Linux was born, Linus Torvalds released the kernel program running on the 386 machine.

2008: Google releases Linux-based mobile OS Android.

second, the gun plan

Launched in 1984 by the famous hacker Richard Stallman, gun was supported by the Free Software Foundation, which is also the main source of the gun's funding to build a free Unix system, with the basic principles of source code sharing and sharing of ideas.

Gun is a recursive abbreviation for "Gun's not Unix".

Linux is based on the copyleft software model for publishing, in fact, Copyleft is a new name against the copyright, is the general Public license of the Gun Project, the GPL is issued by the Free Software Foundation for Computer Software Protocol certificate, The software that uses the certificate is called Free software, and the GPL guarantees that anyone has the right to copy and update the new source code, and that the source code is provided without additional charges, but you cannot state that you did the original work or were made by someone else.

Linux can be said to be an upgraded version of the clone of Unix, Linux is also part of the gun plan, and windows such as the patent-related operating system, Linux is still open and open source code and continue to expand.

third, Linux basic knowledgeWhat is 1.Linux?

Linux is a free-to-use and free-to-propagate Unix-like operating system, a multi-tasking, multi-user, multithreaded and multi-CPU operating system based on POSIX and UNIX.

extension: gnu/linux What is this thing?

Linux is just an operating system kernel, and GNU offers a lot of free software to enrich the various applications on top of it .
So, strictly speaking, the word Linux itself only represents the Linux kernel, but in fact people are accustomed to using Linux to describe the entire Linux kernel, and use the GNU engineering various tools and databases of the operating system. Linux software based on these components is known as a Linux distribution. Generally speaking, a Linux distribution kit contains a large number of software, such as software development tools, databases, Web servers (such as Apache), X Window, desktop environments (such as GNOME and KDE), office suites (such as OpenOffice.org), and so on.
The vast majority of Linux kernel-based operating systems use a large number of GNU software, including a shell program, tools, libraries, compilers and tools, and many other programs, such as Emacs. It was because Linux used many GNU programs that Dr. Richard Stallman, the founder of the GNU program, proposed renaming the Linux operating system to gnu/linux. But some people only call the operating system "Linux".
Some Linux packages, including Debian, are called "Gnu/linux". But most commercial Linux suites still call the operating system Linux. Some people also think that the term "operating system" refers to the kernel of the system, other programs are only application software, so that the kernel of the operating system is called Linux, and the Linux suite is based on the Linux kernel to join the various GNU tools.
Some people who refuse to use "Gnu/linux" as the operating system name say:
1. Linux is catchy; the name is short and good to remember;
2. Dr. Richard Stallman was not asked to change its name until the 1990 's, when Linux became popular.

The above content is quoted from Lu Wei blog, address: https://www.cnblogs.com/nerrissa/articles/5613739.html

2.Linux Main Purpose

Used primarily as a server, especially a network server. There is also a small part to do user personal computer system, such as Ubuntu Kylin, or professional system use, such as Kali LInux.

3.Linux Common Desktop environment (referenced from CSDN, address: 60152071)

1) KDE

KDE was developed from 1996 onwards, and it was released in the first version in 1998. KDE is the easiest desktop environment to customize, which means you can customize everything in the desktop environment. It is built on the basis of modern technology such as QT. Many popular Linux distributions offer KDE, such as Ubuntu, Linux Mint, OpenSUSE, Fedora, Kubuntu, PC Linux OS, and many other distributions.

KDE is the easiest to customize in all desktop environments. In other desktop environments, you need several plugins, window components, and tuning tools to customize the environment, and KDE plugs all the tools and widgets into the system settings. With the Advanced Settings Manager, you can control everything, without any third-party tools, you can beautify and adjust the desktop according to user's preferences and requirements.

KDE's Plasma 5 is the most advanced desktop environment in history, with many improvements, focusing primarily on the visual experience (better launcher, menus and notifications) and ease of use on different devices. The plasma can be run faster and even compatible with older, lower-provisioning hardware.

Some of the default applications in the KD environment include: Dolphin (file Management tool), Konsole (terminal), Kate (text Editing Tool), Gwenview (Image viewing tool), Okular (document and PDF viewing tools), Digikam (photo editing and finishing tools), KMail (email client software), Quassel (IRC client software), K3B (DVD burning program), Krunner (launcher), and more.

Advantages:

· First in the most powerful desktop environment

· Highly customizable

· New and beautiful appearance

· Compatible with slower/older hardware

Disadvantages:

· Some components, such as kmail, are too complex for the average user.

· KMail configuration improvements are not easy for beginners.

2) MATE

Mate is a desktop environment derived from the now-unattended Gnome 2 code base. It is named after the South American plant Paraguay tea. Using a new name instead of using gnome avoids conflicts with GNOME 3 components. Mate comes from a disgruntled user who doesn't like Gnome 2 replacing the GNOME shell to update the desktop.

Mate makes you feel like you're using an old desktop environment, but it's a combination of many improvements in the interface over the years. Mate is also great for low-provisioning computers, so if you have an older or slower computer, you can use mate.

Mate is also a popular Linux distribution, such as Ubuntu, Linux Mint, Mageia, Debian, and many more distributions. Ubuntu Mate Header is the official version.

"Welcome to the official Ubuntu Mate version of the first release. It is now easier for users to update the software because all components are now in the Ubuntu Software Library. ”

The apps that MATE comes with include: Caja (file Management tool), Pluma (text Editing Tool), Atril (document viewing tool), Eye of MATE (image viewing tool), and many other programs. Mate is a simple, lightweight desktop environment for users who don't need all the extra features of other fully functional desktop environments.

Advantages:

· Well-compatible with older/slower computers

· Lightweight desktop environment

Disadvantages:

· Not currently

3) Cinnamon

Similar to mate, Cinnamon is another desktop environment developed by the Linux Mint team for unhappy gnome users. But the difference between cinnamon and mate is that it builds on GNOME 3 technology. Cinnamon is new and actively developed, but this excellent desktop environment has not diminished in functionality because of novelty.

Cinnamon has a variety of features not in desktop environments like gnome and unity. Cinnamon is a highly customizable desktop environment that does not require any external plug-ins, window components, and adjustment tools to customize the desktop. Cinnamon can even download and install themes by setting up the manager itself, without even having to open an Internet browser.

Thanks to all the great features required, cinnamon is convenient for any new user who has just come into contact with Linux. Many users abandon Linux because they don't understand how Linux works, but I strongly recommend that novices start with the Cinnamon desktop environment.

Many popular Linux distributions offer their own versions of cinnamon, such as Ubuntu, Fedora, OpenSUSE, Gentoo, and Arch Linux. Cinnamon is the default desktop environment for Linux Mint.

Advantages:

· Extremely mature and perfect

· Very familiar to new users

· Make gnome easier to use by deriving some core applications

· Highly customizable

Disadvantages:

Sometimes there may be software errors

4) Gnome

Gnome was first released in 1999. Gnome offers a simple yet classic desktop experience, with few options to customize. In 2011, however, GNOME introduced a new design in Gnome 3, which replaced the traditional desktop experience with the Gnome shell. This, in the end, is not satisfying for GNOME users and many developers, and this dissatisfaction has led to the advent of many other desktop environments, such as mate and cinnamon.

But even after that, Gnome's way of doing it is still widely used. Gnome has the core idea of a simple, fast-running desktop environment, which is why GNOME is still simple and fast to run. Customization can be achieved by installing third-party applications and tools.

Gnome may be suitable for those users who often do not adjust the system frequently. That's why GNOME doesn't even include some simple adjustment options, such as changing the theme or even changing the font. In terms of these two basic adjustments, the user will need to install the GNOME tuning tool. So, in general, GNOME is not highly customizable by default, but can be implemented through third-party applications/tools.

Gnome is used as the default desktop environment in Fedora and is available in several popular Linux distributions, such as Ubuntu, Debian, openSUSE, and many other distributions.

Advantages:

· Simple and easy to use

· Add-ons to extend functionality

Disadvantages:

· Lack of many features owned by other desktop environments

· Plug-in management is poor

5) Unity

Unity is a shell developed by canonical, the company that developed Ubuntu. Unity runs on the GNOME desktop environment, using all the core GNOME applications.

It was originally designed to run on netbooks to make better use of valuable screen space. But Gnome decided to go his own way and not accept some of the changes proposed by the Ubuntu team, and canonical the steps to develop his own shell, which is better suited to its requirements.

Unity's first version was released in 2010; Since then, unity has been improved several times. Today, as with several other desktop environments, unity can also be installed on other distributions.

Unity uses a different user interface. Unity has a launcher on the left and a search icon at the top of the launcher, also known as Dash. When you search for files on dash, you will not only give search results from your hard drive, but also search results from online sources, such as Google drives, Facebook, Picasa, flick, and more.

Unity also provides the option to hide the launcher, and touch the sidebar to display it. The user can also increase/lower the sensitivity of the Display launcher menu.

Unity is simple and fast, but unity does not have too many options for customizing the desktop under System settings. To install themes and customize different options, such as whether the system menu should always be visible, or "minimize one click from the Launcher icon", users need to install third-party tools. The CCSM and Unity Tweak tools are a very popular customization tool for the Unity desktop environment.

Unlike KDE, users do not have the option to block/disable notifications in unity. Searching the web, there's a lot of content that explains "How to disable Unity notifications." Although you can disable notifications, it is difficult for new users.

Plus the auto-hide menu, and the lack of official support for major distributions, Unity has become a big help.

Advantages:

· Intuitive interface

· Use of new technologies such as head-up display (HUD)

· Can be customized by third-party applications

Disadvantages:

· The implementation of the notification mechanism is poor

· The default tool for customization is pathetic.

· Inconsistent user interface

4. Log in and out of Linux

1) What is a Linux terminal?

Linux terminals are also known as virtual consoles. Linux uses the character command line to work, the user through the keyboard input command, through the Linux terminal to control the Linux operating system.

2) How to switch the virtual terminal

Linux has a total of 6 virtual terminals, through the combination of key ctrl+alt+f "1~6" to switch.

3) How to determine the normal user and root user?

After the normal user login system prompt for $,root user login After the system prompt is #.

4) Exit command

Exit

5) shut down the machine

Init 0

Attached: Linux system operating level

Run Level 0 (init 0): System down state, the system default RunLevel cannot be set to 0, otherwise it will not start normally
RunLevel 1 (init 1): Single user working status, root privilege, for system maintenance, remote login Forbidden
RunLevel 2 (init 2): Multi-User State (no NFS)
Run Level 3 (init 3): Full multiuser State (with NFS), enter console command line mode after login
Run Level 4 (init 4): System not used, reserved
Run Level 5 (init 5): X11 console, login to GUI mode
Run Level 6 (init 6): The system shuts down gracefully and restarts, the default runlevel cannot be set to 6, otherwise it will not start normally

Linux rookie takeoff Road "two" Linux basic knowledge