1. Click on the menu bar, the "Drawing -> a straight line."
2. Click the Drawing toolbar "draw the line command" press 
.
3. Enter the Line at the command line and press Enter.
After the execution command, the command line displays the following information:
Command: Mx_Line
Specify first point:
Specified under one point:
Specify next point or [(U)]:
Specify next point or [closed (C) / abandoned (U)]: