Here are the commands for switching between headphones/speakers with headphones plugged in. Easy to put into shell script/s...

dbus-send --type=method_call --dest=com.nokia.osso_hp_ls_controller /com/nokia/osso_hp_ls_controller com.nokia.osso_hp_ls_controller.loudspeaker.force_ loudspeaker_on

dbus-send --type=method_call --dest=com.nokia.osso_hp_ls_controller /com/nokia/osso_hp_ls_controller com.nokia.osso_hp_ls_controller.loudspeaker.force_ loudspeaker_off