> There is nothing specific to gnome, kde or xfce in xdg tools. yes there is (in xdg-open):
detectDE ... case "$DE" in kde) open_kde "$url" ;; gnome) open_gnome "$url" ;; xfce) open_xfce "$url" ;; generic) open_generic "$url" ;; *) exit_failure_operation_impossible "no method available for opening '$url'" ;; esac -- and the generic just run firefox. pavel