By way of illustration, below is the in-code documentation for Miriad task varplot which uses the ``directives'' noted previously.
c= varplot - Plot uv variables c& lgm c: uv analysis, plotting c+ c VARPLOT makes X,Y plots selected variables from a uv data set. c Only integer, real, and double precision variables maybe plotted. c When curser is in the plot window, the following keys are active: c X - expand window in X to give one column of plots c Y - expand window in Y to give one row of plots c Z - expand window in both X and Y to show only one plot c N - step to "next" plot in x or y or both depending on expansion c@ vis c Miriad uv data-set. No default. c@ device c PGPLOT plotting device. No default. c@ xaxis c Name of variable to be plotted along x-axis. Default is ut time. c@ yaxis c Name of variable to be plotted along y-axis. No default. c@ multi c Make multiple plots or a single plot? Yes yields multiple plots, c No yields a single plot with multiple lines as needed. Default c is yes. c@ compr c Compress number of x or y variables to be plotted by averaging c over spectral windows. Currently only SYSTEMP can be averaged. c--The task's name is ``varplot'', its one-line description is ``Plot uv variables'', the responsible programmer is ``lgm'', and the program is categorized as both a ``uv analysis'' program and a ``plotting'' program. It has a general description (the text following the c+ line), and it has 6 keywords that the user may set: ``vis'', ``device'', ``xaxis'', ``yaxis'', ``multi'', and ``compr''.