useful for script to be able to alert setbg that something has changed. For
example, a script named rmbg might look at ~/.setbg to get the name of the
current background image file and remove it then signal setbg with SIGUSR1 to
useful for script to be able to alert setbg that something has changed. For
example, a script named rmbg might look at ~/.setbg to get the name of the
current background image file and remove it then signal setbg with SIGUSR1 to