fontviewer <fontFilename> [-b <backgroundcel>] [-t
<textfilename>]
The arrow keys let you scroll around the displayed font cel. The A button forces a reload of the font from disk, so that you can work on a font, save a new version of it, and just hit A to view the results without having to stop/restart the program. The C button toggles between x1 and x2 magnification of the displayed font. The B button toggles the background cel (if any) on and off.