This chapter is a very simplified introductory manual to GREG designed for occasional user who just want an introduction or better, a recipe. It just describes by means of a commented procedure, how to obtain a standard plot for the most usual cases. A user will often want to do more than described here. This is usually not only possible, but even easy. However, such user will have to understand fully the basic concepts of GREG and to read more or less completely the GREG MANUAL.
Before starting, remember that GREG keeps track of all effective commands in an internal buffer for replay capabilities used mostly for repetitive actions and in a log file for post-session control. This log file can be replayed by GREG as any other valid procedure of GREG commands, thus making of GREG a safe system protected against system (or internal...) crashes.
You must know also that GREG uses virtual memory to store all plot coordinates in a device independent way. Hence a plot is entirely independent of any graphic device. You can turn off your graphic device, provided you do not exit from GREG your plot is still available. This Virtual Plot storage also implies that your plot and the way you display it are really two different things. While it may seem confusing at the beginning, this make possible very nice features such as internal Zooming, corrections of erroneous part of the plot and a fast Hardcopy system.