#!/bin/bash
file_manager=nautilus
case "$DESKTOP_SESSION" in
mate)
[[ -f /usr/bin/caja ]] && file_manager=caja
;;
xfce|xfce4)
[[ -f /usr/bin/thunar ]] && file_manager=thunar
;;
cinnamon)
[[ -f /usr/bin/nemo ]] && file_manager=nemo
;;
kde|kde4)
[[ -f /usr/bin/dolphin ]] && file_manager=dolphin
;;
lxde)
[[ -f /usr/bin/pcmanfm ]] && file_manager=pcmanfm
;;
# others?...
esac
shift
exec $file_manager "$@"
exit 0