For example, you may have the GIF weather maps of the United States, but only want to display your general region of the country. When specified, tells xv to automatically issue an AutoCrop command whenever an image is first displayed. Automatically issues a 4x3 command whenever an image is loaded. Automatically issues a 'vertical flip' command whenever an image is loaded. Automatically rotates the image by the specified amount whenever an image is loaded.
Positive values rotate the image clockwise, negative values rotate the image counter-clockwise.
This is most useful when you are using certain greyscale X displays. While xv attempts to determine if it's running on a greyscale display, many X displays lie , and claim to be able to do color. On these displays, if you don't specify -mono , what you will see is a greyscale representation of one of the RGB outputs of the system. The -mono option corrects this behavior. White becomes black, and black becomes white.