Other Command-line Interfaces
The command line provides an interface between programs as well as the user. In this sense, a command line is an alternative to a dialog. Editors and data-bases present a command line, in which alternate command processors might run. On the other hand, one might have options on the command line which opens a dialog box. The latest version of 'Take Command' has this feature. DBase used a dialog box to construct command lines, which could be further edited before use.
Programs like Basic, Diskpart, Edlin, and QBasic all provide command-line interfaces, some of which use the system shell. Basic is modeled on the default interface for 8-bit Intel computers. Calculators can be run as command-line or dialog interfaces.
There are a number of pre-mouse games (like King's Quest 1-3), which relied on the user typing commands at the bottom of the screen. One controls the character by typing commands like 'get ring' or 'look'. The program returns a dialog which describes how the character sees it, or makes the action happen. The text adventure The Hitchhiker's Guide to the Galaxy, a piece of interactive fiction based on Douglas Adam's book of the same name, is a teletype-style command-line game.
The most notable of these interfaces is the STDIO interface, which allows the output of one command to be passed to the input of another. Text files can serve either purpose as well. This provides the interfaces of piping, filters and redirection. Under Unix, devices are files too, so the normal type of file for the shell used for stdin,stdout and stderr is a tty device file.
Another command-line interface allows a shell program to launch helper programs, either to launch documents or start a program. The command is processed internally by the shell, and then passed on to another program to launch the document. The graphical interface of Windows and OS/2 rely heavily on command-lines passed through to other programs – console or graphical, which then usually process the command line without presenting a user-console.
Programs like the OS/2 E editor and some other IBM editors, can process command-lines normally meant for the shell, the output being placed directly in the document window.
One should remember that the 'address line' in a web browser is in fact a command line, even to the thing about about:blank interface. One can program extra commands for a web browser, say to open the registry at a given item, by using the reg: keyword.
On the other hand, features like command history and editing are not nesseccarily part of the command-line interface.
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