To modify the gnome desktop dock (i.e. launcher or launchpad) from the command line an easy way is to perform the following:
/usr/bin/dbus-launch dconf write /org/gnome/shell/favorite-apps "['firefox.desktop', 'org.gnome.Nautilus.desktop', 'org.gnome.Terminal.desktop', 'terminator.desktop', 'gnome-control-center.desktop']"
This above will add Firefox, The File Manager, Terminal, Terminator and Gnome Settings to the desktop