command interpreter

<operating system> A means of communication between a program and its user, based solely on textual input and output. Commands are input with the help of a keyboard or similar device and are interpreted and executed by the program. Results are output as text or graphics to the terminal. Command line interfaces usually provide greater flexibility than graphical user interfaces, at the cost of being harder for the novice to use. Consequently, some hackers look down on GUIs as designed For The Rest Of Them. (1996-01-12)

<software> (Or "option", "flag", "switch", "option switch") An argument to a command that modifies its function rather than providing data. Options generally start with "-" in Unix or "/" in MS-DOS. This is usually followed by a single letter or occasionally a digit. More recently, GNU software adopted the --longoptionname style, usually in addition to traditional, single-character, -x style equivalents. Some commands require each option to be a separate argument, introduced by a new "-" or "/", others allow multiple option letters to be concatenated into a single argument with a single "-" or "/", e.g. "ls -al". A few Unix commands (e.g. ar, tar) allow the "-" to be omitted. Some options may or must be followed by a value, e.g. "cc prog.c -o prog", sometimes with and sometimes without an intervening space. getopt and getopts are commands for parsing command line options. There is also a C library routine called getopt for the same purpose. (2007-02-18)

<operating system> A program which reads textual commands from the user or from a file and executes them. Some commands may be executed directly within the interpreter itself (e.g. setting variables or control constructs), others may cause it to load and execute other files. Unix's command interpreters are known as shells. When an IBM PC is booted BIOS loads and runs the MS-DOS command interpreter into memory from file COMMAND.COM found on a floppy disk or hard disk drive. The commands that COMMAND.COM recognizes (e.g. COPY, DIR, PRN) are called internal commands, in contrast to external commands which are executable files. (1995-03-16)

A command-line interpreter or command-line processor uses a command-line interface (CLI) to receive commands from a user in the form of lines of text. This provides a means of setting parameters for the environment, invoking executables and providing information to them as to what actions they are to perform.

In computing, a shell is a computer program that exposes an operating system's services to a human user or other programs. 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 computer science, an interpreter is a computer program that directly executes instructions written in a programming or scripting language, without requiring them previously to have been compiled into a machine language program. An interpreter generally uses one of the following strategies for program execution:

<theory> Geoff Burn defines evaluators E0, E1, E2 and E3 which when applied to an expression, reduce it to varying degrees. E0 does no evaluation, E1 it evaluates to {weak head normal form} (WHNF), E2 evaluates the structure of a list, i.e. it evaluates it either to NIL or evaluates it to a CONS and then applies E2 to the second argument of the CONS. E3 evaluates the structure of a list and evaluates each element of the list to WHNF. This concept can be extended to data structures other than lists and forms the basis of the {evaluation transformer} style of strictness analysis. (1994-12-12)

Ku is a fictional language appearing in the 2005 drama/thriller film The Interpreter. In the film, Ku is a language spoken in the fictional African country of Matobo.

A console application is a computer program designed to be used via a text-only computer interface, such as a text terminal, the command-line interface of some operating systems (Unix, DOS, etc.) or the text-based interface included with most graphical user interface (GUI) operating systems, such as the Windows Console in Microsoft Windows, the Terminal in macOS, and xterm in Unix.