When you first launch AutoCAD, you will see the main body of the screen, known as the Graphics Screen. This is where a drawing will be displayed and edited. The rest of the AutoCAD interface is how you access and enter AutoCAD commands and change settings in the AutoCAD drawing. ...

Controls the size of the crosshair. The allowable range is from 1 to 100 percent of the total screen. At 100% the ends of the crosshair are never visible. When the size is decreased to 99% or below, the crosshairs have a finite size, and the crosshairsâ ends are visible when moved to the edge of the graphics area. The default size is 5%.

Some commands evoke dialog boxes which are typically used to enter information or change settings. The filedia command suppresses display of the file dialog boxes.

All AutoCAD commands can be typed in at the command line. Many commands also have one or two letter aliases that can also be typed as shortcuts to the commands.
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Source: fetweb.ju.edu.jo