(i) Linux--linux basic concepts

Linux is a free and open source Unix-like operating system that uses the Linux kernel. There are many different Linux distributions that can be installed on a wide variety of computer hardware devices, from phones, tablets, routers and video game consoles, to desktop computers, large computers and supercomputers. Linux is a leading operating system, and the world 's fastest computing supercomputer is running Linux operating systems.

LinuxThe operating system is also the most famous example of free software and open source development. Just followGnugeneral Public License,any person or institution is free to useLinuxall the underlying source code, and can also be freely modified and republished. Strictly speaking,LinuxThe word itself only meansLinuxkernel, but in fact people have become accustomed to usingLinuxto describe the whole based onLinuxkernel, and useGnuEngineering various tools and databases of the operating system (also known asGnu/linux). Typically,Linuxbe packaged into altar computers and servers.Linuxrelease version. Some of the popular mainstreamLinuxrelease, includingDebian(and its derivative versionUbuntu),Fedoraand theOpenSUSEand so on. Kernel+softwares+toolsis thatLinux distribution

Common operating       Systems -Server- side operating system: Linux, UNIX,        Windows Server- standalone operating system: Windows (DOS, Ucdos, Win95, Win98, Win2000, XP, Vista, Win7 , Win8)                         MAC, Linux (Ubuntu)       -Mobile OS Android, IOS, Windows phone

famous Linux distributions:

Red Hat,Fedora Mandriva Novell SuSE Debian Slackware Gentoo Ubuntu CentOS

1. Linux features

Open, multi-user, multi-tasking, rich network functions, reliable system security, good portability, standard compatibility, good user interface (command interface, graphical interface, etc.), excellent speed performance.

2. composition of Linux

1. Kernel: Is the heart of the system, is the core program of running programs and managing hardware devices like disk and printer.

2,Shell: Is the system user interface, provides the user and the kernel to interoperate the interface. It receives the command entered by the user and sends it to the kernel to execute, which is a command interpreter. But it is not only a command interpreter, but also a high-level programming language,shell programming.

3, File system: File system is the file stored on disk and other storage devices on the organization method,Linux supports a variety of file systems, such as ext3,ext2,nfs,smb,iso9660 and so on.

4, application: Standard Linux operating system will have a set of applications such as x-window,open Office and so on.

3. Linux version

1. Kernel:Linux kernel Kernel Current stable version 3.4 http://www.kernel.org/

2, Release: is a number of vendors to the Linux system kernel and application software and documents packaged together, and provide some installation interface and system settings management tools, a package of a collection,

For example RedHat Linux , Debian , Ubuntu, Novell/suse Linux and so on.

3, ubuntu ubuntu first release is in 2004 year 4.10 Span style= "font-family: the song Body;" > In 2009 year 4 month 23 date released, so the version number is 9.04

4. Linux Development and future

now, there are a lot of companies that are using Linux operating system,Linux operating system from the desktop to the server, from the operating system to the embedded system, from the fragmented application to the entire industry has been embryonic. the Linux server operating system occupies more and more market share in the whole server operating system market pattern, and has formed the large-scale application situation.

why learn about Linux operating         systems 1. Most servers are Linux-based, and Jee is deployed to        the server 2. Some enterprises and schools use Linux research         and development and teaching 3. Many embedded development Linux          4. Cloud computing, Big Data is the cluster network  Linux:centos

5. Android

Android is a Linux -based open-source operating system.

6. Linux Basic directory structure

　　　　　　　　　

Bin holds binary executables (ls,cat,mkdir , etc. )

Boot holds various files used for system boot

Dev for storing device files

ETC Storage System configuration file

Home Store The root directory of all user files

Lib holds shared libraries and kernel modules needed to run programs in the file system

MNT system Administrator installs the temporary file system installation point

Placement of optional application packages that opt for additional installation

Proc virtual file system, storing the current memory mapping

Root Super User directory

Sbin Store binary executable files, only root to access

TMP is used to store various temporary files

USR for storing system applications, more important directories /usr/local local Administrator software installation directory

var is used to store files that need to change data at run time

(i) Linux--linux basic concepts