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As English promptly in is IT an invitation to the user designates an input ( input ) to make. There are usually different labels that indicate different programs or modes. Different characters are used as prefixes for this on text-based systems . A prompt can often be switched off and in some cases can also be changed and thus individually adapted.

A direct translation of input prompt into German is command prompt , a term that, however, describes the command line interpreter under Windows .

Working principle

(Mainframe English mainframe ) were often Telegraph used spending both spending as well as text entries. To distinguish between the output of a program and the input by the user, individual characters were placed in front so that when reading the printout it was clear what a user had entered and what the output of a program was. Different prefix characters could also e.g. B. make a message of the operating system immediately distinguishable from the message of a program. This principle has been adopted on terminals.

On microcomputers , such as the Apple IIe , messages are displayed in text mode on a computer monitor and different characters are also used as a prompt.

With operating systems , a “ command prompt ” signals that the computer is expecting an input. Here, too, there are different characters - for example, Unix shells have different prompt characters that can be adapted. The prompt can also be set under PC-compatible DOS . In this way, additional information can also be output with the prompt, such as the current path in which a command line interpreter is currently located.

An example is the DOS command PROMPT(see list of DOS command line commands # P ):


Here is $Pthe current path ( path , see directory structure ) and $Gthe greater-than sign ">", a typical output immediately after startup of MS-DOS is about C:\>. In early versions of DOS the path was omitted, which equates PROMPT $Gand always results >.


Time-sharing systems were used on many mainframes , such as the System / 360 from IBM . An example of this is the Michigan Terminal System (MTS), which was in use at various universities between 1967 and 1999. The MTS could be used in two ways: in batch mode without any further interaction with the user, or in terminal mode , i.e. via interactive access via a terminal . In this interactive mode, different prefix characters are used (roughly preceding characters in German ) that prompt the user for an input: English "prompt the user for input" . On the MTS these were:

prefix characters of the Michigan Terminal System
character Mode or program description
# MTS command mode Input prefix of the MTS, but also in front of the output of the MTS
? general Eingabepräfixzeichen ( prompting prefix character ) Example: input prefix of the $CALCcommand
: MTS file editor
> $LIST and $COPY Output and input prefix
+ Symbolic Debugging System  (SDS)
. system loader Outputs of the loader
@ MTS message system
  empty character ( blank ); User programs

The prefix is ​​an important indicator of which mode or program the system is currently in. For example, if you started with $CALCthe computer function, only arithmetic entries could be processed until the computer STOPfunction was terminated with the command - only then were the MTS functions available again. With the other prompt prefix, however, you can always see which mode the system is in and which entries are therefore possible.

Example (entries are fettshown):


The SET PFX=OFFprompt could also be switched off with the command . B. could be useful for printing a report.

See also

Individual evidence

  1. a b Apple IIe technical reference manual . Addison-Wesley Publishing, University of California 1986, ISBN 978-0-201-17720-6 , pp.  60 (English, limited preview in the Google Book Search): “… character, called simply a prompt. The prompt indicates to the user that the program is waiting for input. Different programs use different prompt characters, helping to remind the user which program is requesting the input. "
  2. Apple IIe technical reference manual . Addison-Wesley Publishing, University of California 1986, ISBN 978-0-201-17720-6 , pp.  394 (English, limited preview in Google Book Search): "prompt character: A text character displayed on the screen to prompt the user for some action."
  3. ^ Georg Witzel: Michigan Terminal System . Getting Started: Introduction to MTS. University of Michigan Computing Center, Ann Arbor, Michigan August 1987, pp. 19 (English, full text in the Google book search).
  4. Thomas J. Schriber: Fundamental Use of the Michigan Terminal System . Graduate School of Business Administration, The University of Michigan, Michigan August 1976, p. 2–11 (English, full text in Google Book Search).