What is shell ?

What is shell ?

Sophia Alikhani Sophia Alikhani

Sophia Alikhani

Linux System Administrator

发布日期: 2018年8月26日
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Question 01: Shells

What is shell?

 

Answer: A shell can best be described as a language to communicate with a computer.

Most users operate with the point-and-click language of the desktop but the computer is leading the conversation  in this kind of language.

The user has the passive role of picking tasks from the choice presented by the computer .

It is very difficult for a programmer to include all options and possible users of a command in  the Graphical User Interface(GUI) format .

Thus, GUIs are almost always less capable than the command or commands that form the backend.Shell is an advanced way of communicating with the system because it allows for

two-way conversation.

Interactions in the communication are equal so that new ideas can be tested.

The shell allows the user to handle a system in a very flexible way and allows for task automation.When you mess around in the Linux command line, there's always a program called shell running. When you type commands, it's the shell that reads the commands from your keyboard, processes  them and finally gives them to the operating system.

There are many different shell programs available but on most Linux systems,

bash (Bourne Again Shell) is the default shell.

When you start a shell on your Linux system, it's most likely bash.

There are many shell on Linux and Unix operating system such as sh (Boune Shell) , csh , tcsh, zsh , ksh .

Every Unix operation system has a default shell, for example Sun Solaris default shell is csh or tcsh,  SCO Unix default shell is sh and most of Linux distrobution default shell has bash.

But you can change this default shell on very Linux or Unix operating system for your usage.

Every shell has it's rules for programming. Based on your experience you may want choose one of type of shell .


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