xroot
xroot runs a command every time a given mouse button is pressed on the root window.
§ Installation
In order to build xroot you need the Xlib header files.
Edit config.mk to match your local setup (xroot is installed into the /usr/local prefix by default). Then enter the following command to build and install xroot (if necessary as root).
make clean install
§ Running xroot
xroot gets as argument an command and its arguments and run this command every time the right mouse button is pressed on the root window.
One of the options -l, -m, -r, -1, -2, -3, -4, or -5 can be passed as first argument. Those options indicates, respectivelly, that the left, middle, right or N-th mouse button is to be used instead.
Call xroot on your .xinit or .xsession file in background, before the window manager. As the following:
xroot -l xterm &
Read the manual for more information on running xroot