Название: Bash Scripting: Everything you need to know about Bash Автор: Max Beerbohm
Издательство: Independently published
Год: 2019
Страниц: 140
Язык: английский
Формат: epub, rtf, pdf (conv)
Размер: 10.1 MB
Any recent computer operating system (byrecent, we mean since about 1970) hassome sort of user interface - some way of specifying commands for the operating system to execute. But in lots of operating systems, that command interface was really built in and there was only one way to talk to the computer. Furthermore, an operating system’s command interface would let you execute commands, but that wasabout all. After all, what else was there to do? The Unix operating system popularized the notion of separating the shell (the part of the system that lets you type commands) from everything else: the input/output system, the scheduler, memory management, and all of the other things the operating system takes care of for you (and that most users don’t want to care about).
The shell was just one more program; it was a program whose job was executing other programs on behalf of users. But that was the beginning of a revolution. The shell was just another program thatran on Unix, if you didn’t like the standard one, you could create your own. So bythe end of Unix’s first decade, there were at least two competing shells: the Bourne Shell, sh (which was a descendant of the original Thomson shell), plus the C Shell, csh. By the end of Unix’s second decade, there were a few more alternatives: theKorn shell, (ksh), and the first versions of the bash shell (bash).
What is shell script? It is a file with a set of commands to perform a specific purpose, where the shell executes them in an interactive way you will see the definition through the following example: For example, the joiner box contains tools (screwdrivers, screws, wood, hammer ... etc). He can build chairs, tables, cabinets, etc. Using the same tools, but with a certain composition, he can build anything he wants. This example is very similar to shell scripting. To build anything you want, you must use the right tools and call them commands or programs, which are mentioned above.
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