1、 1 19001900 英文单词，英文单词，1 1 万英文字符，中文万英文字符，中文 33003300 字字 外文原文外文原文 Introduction to shell In this chapter, you will learn: 1)About shells in Unix history 2)Not to be afraid to use the Command Line Interface 3)How to find help and discover autocompletion 4)That using the shell is great, so great ! 1 Basi
2、c definition A shell is a software providing a text-based interface to users. Thereby, they can use their computers.It is also called “command interpreter“. Indeed, the shell executes commands that the user types. Basically, there is two way to really use a computer: with a shell, by typing commands
3、, or by a Graphical UserInterface (GUI), including buttons, menu, or more recently mouse support, ect. These two interfaces are often opposed, but you better may consider them as complementary. 2 History 2.1Introduction to history of user interfaces The first computers were very basic and offered lo
4、w performances. Moreover, at the beginning of computingscience, there was quite a few number of softwares and features. As you can imagine, only text-based interfaces where available, because of the lack of computing performances,the lack of graphical interface API (Application Programming Interface
5、). Furthermore, there was no real need of graphical interfaces for a long time: while applications remained limitedand ease of use, or that computers where only used as servers or specific business applications, nobody complained about the user experience. Graphical Interfaces began to appear, but m
6、any were still text-based. Graphical User interfaces as we know nowadays expanded a lot thanks to the fight between Apple and Microsoftfor the end- user, familial computing market. 2.2 History of Unix shells Unix was one of the first Operating System that didnt integrate the shell too deeply. In 2 Unix, the shell is a standalone program with very few permissions. It has led to a succession of alternative shell developments and improvements.We can divide shells into four generations: - Fir
