Export display (for controlling rhythmbox)
In '.bashrc'
export DISPLAY=:0.0
export `grep -z DBUS_SESSION_BUS_ADDRESS /proc/$(pgrep -o rhythmbox)/environ 2>/dev/null` >/dev/null
Then:
$ rhythmbox-client --next
$ rhythmbox-client --previous
$ rhythmbox-client --volume-up
...