What is a shell?

A lot of content is easy to confuse, so it's better to sort out some concepts here.

Shell is shell, meaning is a shell outside the operating system kernel, used to interact with the user, which is more commonly used on the server, so do not use the UI interface, can reduce the running space and bugs

So the shell is very important in Linux, which is used as a server system, so the shells provided by Linux are generally very powerful.

Even Linux has a lot of shells, different shells provide different ways to interact with the operating system kernel, but basically it is a command line form, of course, these command lines can also be written as a file, as a batch or script

Microsoft's previous system is no UI, that is, DOS, from the function of the DOS input command to use the operating system kernel and the shell function is similar, but the error is in development, then the DOS system was abandoned, the new system launched, but still provide shell program to access the operating system kernel, Although not called Shell, but the empty energy is the same, and then Microsoft's server market has been less than Linux so they want to develop shell, so later with the PowerShell this thing, this is called Shell, But in fact, whether DOS or CMD or PowerShell provides functionality that basically resembles a variety of Linux shells.

It is important to note that these different shells may have the same command name, but it does not mean that all the syntax for using these shells is the same, including Cmd and PowerShell, but at least most should be similar

and the input PowerShell in CMD can be switched to PowerShell, which is still

There is also a shell called Pythonshell, this thing is called. It is the shell of the Python interpreter, the shell of the Python interpreter interacting with the user.

Resources:

http://www.zhihu.com/question/22611859

Http://www.cnblogs.com/ceachy/archive/2013/01/31/PowerShell_vs_Cmd.html

Http://os.51cto.com/art/201302/380594.htm

Http://www.360doc.com/content/11/0308/18/4842470_99299185.shtml

http://blog.csdn.net/hitlion2008/article/details/7467252

Http://www.computerhope.com/issues/chdos.htm

http://segmentfault.com/q/1010000000316935

What is a shell?