Petit script bash pour intervertir deux sinks de pulseaudio. Par exemple pour passer le son de la carte interne vers un casque usb et inversement en une pression de touche. Trouvé ici: http://snipplr.com/view.php?codeview&id=70531 et un peu adapté.

soundswitch.sh

#!/bin/bash
#
# Sound output switcher using PulseAudio,libnotify
#
# by Alda <alda@leetchee.fr>
# inspired by Mickaël Quirin <eephyne[guess what put here]gmail.com
# and Anton Veretenenko <anton[email sign]veretenenko.ru>

notify_show=1
notify_delay=2000

# There you must put the name of the two devices you want to permute
# You can find them with `pacmd list-sinks`
default_output_name="alsa_output.pci-0000_00_1b.0.analog-stereo"
alt_output_name="alsa_output.usb-0d8c_USB_Sound_Device-00-Device.analog-surround-51"

default_output=`pacmd list-sinks | grep -B1 "<$default_output_name>" | grep index | sed -r "s/^.* index: //"`
alt_output=`pacmd list-sinks | grep -B1 "<$alt_output_name>" | grep index | sed -r "s/^.* index: //"`

active_device=`pacmd list-sinks | grep -i -E '\* index' | sed -r "s/^.*\* index: //"`


active_device=`pacmd list-sinks | grep -i -E '\* index' | sed -r "s/^.*\* index: //"`

if [ "$active_device" == "$alt_output" ]
then
    pacmd "set-default-sink $default_output"
    test=`pacmd list-sink-inputs | grep -i -E 'index:'`

    while read -r line;
    do
        sink=(`echo $line | sed -r s/^.*index:\ //`)
        pacmd move-sink-input $sink $default_output;
    done <<< $test

    if [ $notify_show -eq 1 ]
    then
        notify-send -u normal -t $notify_delay -i gnome-sound-properties "Alternative OFF" "Sound output switched to internal audio"
    fi

else

    pacmd "set-default-sink $alt_output"
    test=`pacmd list-sink-inputs | grep -i -E 'index:'`

    while read -r line;
    do
        sink=(`echo $line | sed -r s/^.*index:\ //`)
        pacmd move-sink-input $sink $alt_output;
    done <<< $test

    if [ $notify_show -eq 1 ]
    then
        notify-send -u normal -t $notify_delay -i gnome-sound-properties "Alternative ON" "Sound output switched to alternative audio"
    fi
fi