ref: 989ecb1ad9eab0de1363c8a59a3ed33616e1b8c8
dir: /README/
ifilter ======= Basic image color filters. ifilter reads an image from standard input, applies a color filter and dumps the resulting image to standard output. Available color filters are: - grayscale - sepia - invert - shade - tint usage: ifilter [-f factor] [grayscale|sepia|invert|shade|tint] Note: factor is used for the shade and tint filters and ignored otherwise.