Commands exist to modify the frame, add labels, override the default ticks, change the plotting style, define coordinate ranges and transformations, and include data from files. In addition, grap provides loops, conditionals and macro processing. The GRAP Chapter of the manual provides more information.
Grap actually generates pic(1) codes. Thus, to use grap, one must send the output through pic and then eroff (or troff). For example:
grap myfile | pic -D | eroff
Here's an example of very simple grap input and its output:
.G1 1 2 2 3 3 4 generates 4 6 5 9 .G2
frame ht 1.25i wid 2.25i 1 2 2 3 3 4 4 6 5 9
Created by unroff & hp-tools. © by Hans-Peter Bischof. All Rights Reserved (1997).
Last modified 21/April/97