gmmkctl
Cross platform utility to control the features of the GMMK keyboard.

Compiling (tested with libusb 1.0):
make

USAGE: gmmkctl [command [<args ...>] ...]

Run with no command will indicate the number of devices which it found which it
can control.  Currently it will try to control the first 8 keyboards it finds.

Commands:
help - Shows this list of commands.
devmask <mask> - Set the mask of detected devices which should be controlled by
    the following commands.  By default, all are selected.
mode <num> - Set the mode.  20 is the mode for freely programming the keys, and
    the highest meaningful value.
brightness <num> - Set the brightness.  0 - 4 are meaningful.
delay <num> - Set the delay between animation frames.  Very large values seem to
    be meaningful.  0 - 255
left - Set animation to proceed towards the left.
right - Set animation to proceed towards the right.
colorful - Turn on "colorful" mode.
single - Turn on single color (not colorful) mode.
rate - Adjust polling rate.  Not really tested. 0:125, 1:250, 2:500, 3:1000, 4+:???
color <r> <g> <b> - Set color for single color mode. 0 - 255
keys - Read in human readable numbers from standard input and set key colors.
    Values may be separated by any whitespace.  Seems to work by feeding in a
    file from standard input or with a here word/document.
    first value - Offset key to start programming colors.
    second value - Number of values to follow.
    N additional triplets - R, G and B values for each key color.  0 - 255