shell script to switch pulseaudio output device

audio-switch.sh

#!/bin/sh

# based on a script from a now deleted askubuntu answer on this question http://askubuntu.com/questions/71863/how-to-change-pulseaudio-sink-with-pacmd-set-default-sink-during-playback
# the script linked in the answer is still available at https://github.com/mpapis/home_dotfiles/blob/master/bin/mypa though

# dependencies: pulseaudio pacmd awk xargs grep volumeicon
# optional dependencies: zenity (for gui switch)

# this script assumes you are using volumeicon as a tray icon and will restart it on switch
# if you do not use volumeicon you should remove the 2 lines in switch_sink()

function list_sinks()
{
  pacmd list-sinks | grep -E 'index:|name:'
}

function switch_sink_default()
{
  echo switching default
  pacmd set-default-sink $1 || echo failed
}

function switch_sink_applications()
{
  echo switching applications
  pacmd list-sink-inputs |
    awk '/index:/{print $2}' |
    xargs -r -I{} pacmd move-sink-input {} $1 ||
      echo failed
}

function switch_sink()
{
  switch_sink_default      "$@"
  switch_sink_applications "$@"
# workaround because volumeicon does not detect a switch of audio output
  killall volumeicon 2>/dev/null 
  (volumeicon &)
}

# Use a zenity gui to switch audio outputs
function switch_gui()
{
# get current output id, all output ids and the sink names
   current_id=$(pacmd list-sinks | egrep '\* index:' | egrep -o '[0-9]+$')
   ids=( $(pacmd list-sinks | egrep 'index:' | egrep -o '[0-9]+$' | tr '\n' ' ') )
   names=( $(pacmd list-sinks | egrep 'name:' | egrep -o '\..*>$' | tr -d '>' | tr '\n' ' ') )

   zen_pars="--list --radiolist --column '' --column 'ID' --column 'Sink_name'"

# construct the zenity command
   for i in "${!ids[@]}"
   do
      if [ ${ids[$i]} = $current_id ]; then
         zen_pars="$zen_pars TRUE"
      else
         zen_pars="$zen_pars FALSE"
      fi
      zen_pars="$zen_pars ${ids[$i]} ${names[$i]}"
   done

# change the audio sink with the switch_sink function
   new_sink_id=$(zenity $zen_pars || echo "")
   if [ -n $new_sink_id ]; then
      switch_sink $new_sink_id
   fi
}

function help_me()
{
  echo "Usage: $0 [gui|list|<sink name to switch to>]"
}

case "${1:-}" in
  (""|list) list_sinks       ;;
  ([0-9]*)  switch_sink "$@" ;;
  (gui)     switch_gui       ;;
  (*)       help_me          ;;
esac