These instructions are for Canon all-in-one printers (printer, scanner, and copier in one unit). These instructions are for the Canon PIXMA MP160, but these instructions can be adapted for other all-in-one printers in the Canon PIXMA series of all-in-one printers. This is done entirely in the terminal. All terminal commands are in boldface.
If you have a point-and-click digital camera made by Canon, you may be able to turn on all sorts of features usually reserved for more expensive SLRs. That includes live histograms, depth-of-field calculation, under and overexposure highlighting, and -- best of all -- shooting your pictures in RAW. The secret is CHDK, an enhanced, free software replacement firmware.