Appendix D. System Variables and Dimension Styles
AutoCAD is a complex program with a vast set of options and settings. You don't need to know everything about AutoCAD to be a productive user, but it does help to be aware of some of the inner workings that let you fine-tune the program.
This appendix covers a few of the details that can help you get tighter control over the way AutoCAD works. You'll find a brief discussion of system variables that give you direct control over options and features. That discussion is followed by a detailed look at dimension styles settings.
System variables let you fine-tune your AutoCAD environment. Most of the system variables control the same options you find in AutoCAD's dialog boxes and palettes. ...