plughwinfo.sh

#! /usr/bin/env bash

usage_and_exit () {
  echo    "Checks if passed arguments are valid audio-playback devices"
  echo    ""
  echo -e "\033[1;37;40mUsage:\033[0m plughwinfo.sh [<parameters>|<playback-devices>]"
  echo    " -l (--list)        Display all available playback devices"
  echo    " -h (--help)        Display this message"
  echo    " <playback-devices> Returns error if one of the passed arguments is not a valid playback-device"
  echo    ""
  echo -e "\033[1;37;40mRequirements:\033[0m"
  echo    " alsa (www.alsa-project.org)"
  echo    ""
  exit 0
}

list_playback_devices () {
  for card_id in $(grep "^\<[0-9]\?\|^ [0-9]" /proc/asound/cards | awk '{ print $1 }');
  do
    card_name=$(cat /proc/asound/card$card_id/id);
    for device_id in $(grep "^device:" /proc/asound/card$card_id/pcm0c/info  2> /dev/null | awk '{ print $2 }');
    do
      for subdevice_av in $(grep "^subdevices_avail:" /proc/asound/card$card_id/pcm0c/info  2> /dev/null | awk '{ print $2 }');
      do
        for subdevice_id in $( seq 0 $(expr $subdevice_av - 1))
        do 
          echo plughw:$card_name,$device_id,$subdevice_id;
        done
      done
    done
  done
}

match_devices () {
  DEVICES=$@
  for i in $DEVICES; do
    if [ $(echo $PLAYBACK_DEVICES | grep $i | wc -l) -eq "0" ]; then
      exit 1
    fi
  done
  exit 0
}


PLAYBACK_DEVICES=`list_playback_devices`

if [ $# = 0 ]; then
  echo "$PLAYBACK_DEVICES"
  exit 0
fi

while [ $# -gt 0 ]; do
  case $1 in
    -h | --help | h)
      usage_and_exit
    ;;
    -l | --list)
      echo "$PLAYBACK_DEVICES"
      exit 0
    ;;
    *)
      match_devices "$@"
  esac
  shift
done