The program is invoked by typing 'discus' at the operating system or at the shell prompt. The program uses a command language to interact with the user. The command 'exit' or a CTRL Z terminates the program.
All commands of DISCUS consist of a command verb, optionally followed by one or more parameters. All parameters must be separated from one another by a comma ",". There is no predefined need for any specific sequence of commands.
DISCUS is case sensitive, all commands and alphabetic parameters MUST be typed in lower case letters.
Only the first four letters of any command verb are significant, all commands may be abbreviated even further. At least a single space is needed between the command verb and the first parameter. No comma is to precede the first parameter. The command verb itself MAY NOT be preceded by any blanks.
Help on the program is obtained by typing "help" or "help <command>" to get specific help on the command <command>. The command may be abbreviated. If the abbreviation is not unique, only the first help topic that matches the command is listed. The first line of the help text gives the syntax of the command that is explained in the following lines. For a few commands the syntax line is repeated for different set of possible parameters.
Further help topics are: