The toughest part of using Adobe Illustrator is certainly managing paths. Because paths are so important to the Illustrator experience, the program has many tools to help you use paths to the fullest. One of these tools is the scissors tool, which lets you cut a path. Get started using the scissors tool.
Draw a rectangle using the rectangle tool.
Set the fill to none and the stroke to black, using the color cubes near the bottom of your toolbar.
Click on the scissors tool in your toolbar, making sure your rectangle is actively selected. The scissors tool sometimes hides under the eraser tool or knife tool.
Click precisely on one of the points of the rectangle using the scissors tool. You have just cut the path, and the rectangle is no longer a closed shape.
Select the white arrow tool. Click on a blank area of canvas to deselect the freshly cut rectangle. Click on a line segment near your cut, dragging the line away. You can clearly see how you cut the path.
Use the scissors tool to cut any path at a point. The path does not need to be a closed shape.