Some parameters offer menus from which you select an option. You do not have to enter the full option string, but merely a string that selects a choice unambiguously. In many cases this can be as little as a single character. Here is an example,
MODE - Method for selecting contour heights /'Free'/ > ? The method used to select the contour levels. The options are described below. "Area" - The contours enclose areas of the array for which the equivalent radius increases by equal increments. You specify the number of levels. "Automatic" - The contour levels are equally spaced between the maximum and minimum pixel values in the array. You supply the number of contour levels. "Free" - You define a series of contour values explicitly. "Linear" - You define the number of contours, the start contour level and linear step between contours. "Magnitude" - You define the number of contours, the start contour level and step between contours. The step size is in magnitudes so the nth contour is dex(-0.4*(n-1)*step) times the start contour level.
where an F would be sufficient to select the "Free" option, but at least two characters would be needed if you wanted "Area" or "Automatic".
Some parameters permit a mixture--a choice from a menu, or a
numerical value within a range. The options are described in full in
KAPPA --- Kernel Application Package