1/15/2024 0 Comments Xonsh vs powershellMultics also introduced the active function, a key concept in all later shells. This procedure acts as an interface between console messages and subroutine. In a 1965 document, the shell is defined as "a common procedure called automatically by the supervisor whenever a user types in some message at his console, at a time when he has no other process in active execution under console control. In 1964, for the Multics operating system, Louis Pouzin conceived the idea of "using commands somehow like a programming language," and coined the term shell to describe it. Common commands would log the user on and off the system, allocate, free, and manipulate devices and files, and query various pieces of information about the system or a user process. The interpreter would execute one of a number of predefined commands, one of which would be to run a user program. This interpreter might be called by different names, such as COMCON on DEC TOPS-10 systems. Many computer users use both depending on the task to be performed.Įarly interactive systems provided a simple command-line interpreter as part of the resident monitor. The relative merits of CLI- and GUI-based shells are often debated. Other possibilities, although not so common, include a voice user interface and various implementations of a text-based user interface (TUI) that are not CLI, such as text-based menu systems. Command-line shells provide a command-line interface (CLI) to the operating system, while graphical shells provide a graphical user interface (GUI). Most operating system shells fall into one of two categories – command-line and graphical. On Microsoft Windows, Remote Desktop Protocol can be used to provide GUI remote access, and since Windows Vista, PowerShell Remote can be used for text-based remote access via WMI, RPC, and WS-Management. On Unix-like systems, Secure Shell protocol is usually used for text-based shells, while SSH tunneling can be used for X Window System–based graphical user interfaces (GUIs). Initially available on multi-user mainframes, which provided text-based UIs for each active user simultaneously by means of a text terminal connected to the mainframe via serial line or modem, remote access has extended to Unix-like systems and Microsoft Windows. In addition to shells running on local systems, there are different ways to make remote systems available to local users such approaches are usually referred to as remote access or remote administration. Since the operating system shell is actually an application, it may easily be replaced with another similar application, for most operating systems. A shell manages the user– system interaction by prompting users for input, interpreting their input, and then handling output from the underlying operating system (much like a read–eval–print loop, REPL). Shells are actually special applications that use the kernel API in just the same way as it is used by other application programs. Most operating system shells are not direct interfaces to the underlying kernel, even if a shell communicates with the user via peripheral devices attached to the computer directly. Operating systems provide various services to their users, including file management, process management (running and terminating applications), batch processing, and operating system monitoring and configuration. Ĭommand-line shells require the user to be familiar with commands and their calling syntax, and to understand concepts about the shell-specific scripting language (for example, bash), while graphical shells place a low burden on beginning computer users and are characterized as being easy to use, yet most GUI-enabled operating systems also provide CLI shells, normally for performing advanced tasks. It is named a shell because it is the outermost layer around the operating system. In general, operating system shells use either a command-line interface (CLI) or graphical user interface (GUI), depending on a computer's role and particular operation. In computing, a shell is a computer program that exposes an operating system's services to a human user or other programs. In the lower right we can see a terminal emulator running a Unix shell, in which the user can type commands as if they were sitting at a terminal. Computer program that exposes an operating system's services to a human user or other programs A graphical interface from the late 1980s, which features a TUI window for a man page, a shaped window (oclock) as well as several iconified windows.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |