In another attempt to diminish the typing for repetitive actions and make some functions easier, a prompt mode has been designed. The fact that most commands querying data offer the same options and have many similar functionalities, makes it a little absurd to have so many command names. This was also the reason to develop the three level structure using options and functions.
The reverse philosophy is faster but needs more typing. The prompt mode is an attempt to combine fast answer time and low typing. An attempt has been done to keep the number of files to a minimum. The program dbms is a large Bourne shell script. When run, it presents a prompt bda> to which commands are issued. The prompt is then modified and contains the command name. An agent has been called, in some similarity with Simbad vocabulary. To the agent prompt, one can enter star numbers, options and parameters, a datatype, depending on the context. One can enter help at any prompt to get a list of the valid answers. The agent help entered at the bda prompt opens a new window which allows to keep it in parallel. The help presents a list of all agents, datatypes and information on each.
At a certain level of complexity, it becomes again difficult to present a simple syntax and easy methods to execute tasks which requires complex selections, with several verbs and a variable number of parameters. Therefore, in this first version of dbms the command mode syntax is used for performing selection, because it is finally the more compact. However the select agent allows to use a syntax like measure ubv> v < 7.5 to select stars with V magnitudes less than 7.5 from the UBV data file.
The complexity is also in the parsing program that analyse the entry line. The shell has been restricted to some standard style. Maybe that writing the program with Perl would bring more facility to do complex entry line parsing.