shell : interpreter, command language (interactive), programming languages (non-interactive, batch BATCH )
In computer science, commonly known as Shell shell (to distinguish core), refers to the software, "provides the user interface" (command parser) . It is similar to command.com and cmd.exe later under DOS. It receives user commands, and then calls the appropriate application.
But it also is a programming language . As a command language commands it interprets and executes interactive user input or automatically interpret and execute a series of preset commands ; as a programming language that defines the variables and parameters, and provides a number of high-level language only the control structure has, including looping and branching .
Shell in the traditional sense refers to the command line of the shell, later if not otherwise stated, shell refers to the command line of the shell .
Text outside the main operating system and interface is called the shell. shell is the outermost layer of the operating system. The interaction between the shell and manage your operating system: waiting for your input, to the operating system interprets your input, and deal with a variety of operating system output.
The shell provides a means of communication between you and the operating system. This communication may be performed in a shell script (non-interactive) mode interactively (from the keyboard, and can immediately get a response), or. shell script file is placed in the shell and a series of operating system commands, they can be reused. In essence, shell script is simply a combination of command-line command to a file inside.