lgsetled is a small C program whose job it is to set the brightness of various LEDs on Logitech G keyboards managed by the kernel driver. The kernel exposes these lights as files in /sys/class/leds, but they are owned by root. As Gnome15 communicates directly with the keyboard when using the kernel drivers, it must be able to write to these files. For this reason lgsetled must be installed with SETUID permissions.
Download the latest lgsetled source from the Source Downloads page and follow the usual source package installation procedure.
./configure --prefix=/usr
make
sudo make install
Ubuntu 10.10 and 10.4 packages are available in the Gnome15 PPA.
First, add the PPA to your sources. You may do this in a number of ways (Synaptic etc), or from the command line:-
sudo add-apt-repository ppa:tanktarta/gnome15
sudo apt-get update
Now install lgsetled.
sudo apt-get install lgsetled