In computing shellis called the interface that interprets typed commands and transmits them to the operating system kernel, kernel. It is usually used on Unix and Unix-like operating systems, so it is also called a Unix shell in Hungarian. It is called a shell because it is the outermost layer of the operating system kernel.

The shell requires the user to be familiar with commands and their operating syntax, as well as understanding shell-specific scripting concepts (such as Bash scripts).

A command line interface (CLI) in addition, the operating system can be controlled through a graphical interface, which does not require the same amount of expertise but puts a greater strain on computer resources. Therefore, most Unix / Linux servers use only command-line interfaces, which require less resources, are more stable, and faster.

Operating systems provide a variety of services to their users, including file management, process management (running and finishing applications), batch processing, and operating system management and configuration.

The shell of most operating systems is not directly connected to the underlying kernel, even if a shell communicates directly with the user through peripherals connected to the computer. Shells are actually special applications that use the kernel API in the same way as other programs. The shell handles the user-system interaction, prompts the user for commands, interprets the input received, and returns the response returned from the operating system to its output. Because the operating system shell is also an application, it can be easily replaced with another shell application.

On Unix-type operating systems, users can choose from several shells that also have unique properties to make it easier to solve different types of tasks, but together they perform important processes after logging in to the operating system to get the system ready for use. .

The most widespread among Unix shell shells is Bash (Bourne Again Shell)but there are a few more well-known:

• Bourne shell
• Dash
• csh
• ksh
• zsh
• PowerShell (Windows)