AutoCAD has hundreds of system variables, many that are managed through dialogs, but still plenty that are managed from the commandline. One of the 2016 highlights, at least for CAD Managers, is the new System Variable Monitor. With this new feature you define a system variable standard. When the settings change from the standard you are notified. Using the dialog you can adjust the variable settings individually or use the Reset All option to reset all settings back to default.