gistfile1.sh

#!/bin/bash

if [ "$1" = '-h' -o "$1" = '--help' ]; then
	me="${0##*/}"
	echo "$me: list ALSA devices and relevant information."
	exit 0
fi

if [ -e '/proc/asound/version' ]; then
	cat '/proc/asound/version'
	echo
fi

for (( i=0; i<100; i++ )); do
	if [ -d "/proc/asound/card${i}" ]; then
		cname="$( cat "/proc/asound/card${i}/id" )"
		echo "Card ${i} (${cname}):"

		for t in 'p' 'c'; do
			case "$t" in
				p) typeString='Playback' ;;
				c) typeString='Recording' ;;
			esac

			for (( j=0; j<100; j++ )); do
				if [ -d "/proc/asound/card${i}/pcm${j}${t}" ]; then
					dname=''
					if [ -e "/proc/asound/card${i}/pcm${j}${t}/info" ]; then
						dname="$( grep -E '^name: ' "/proc/asound/card${i}/pcm${j}${t}/info" 2>/dev/null | cut -d ' ' -f 2- )"
					fi
					echo
					if [ -n "$dname" ]; then
						echo "  * ${typeString} Device ${j} (${dname}):"
					else
						echo "  * ${typeString} Device ${j}:"
					fi
					ownerPID="$( grep -E '^owner_pid' "/proc/asound/card${i}/pcm${j}${t}/sub0/status" 2>/dev/null | tr -cd '0-9' )"
					if [ -n "$ownerPID" ]; then
						tgid="$( grep -F 'Tgid:' "/proc/${ownerPID}/status" 2>/dev/null | tr -cd '0-9' )"
						if [ -n "$tgid" ]; then
							ownerPID="$tgid"
						fi
						ownerName="$( cat "/proc/${ownerPID}/comm" 2>/dev/null )"
						echo "    used by: ${ownerName} (PID ${ownerPID})"
					fi
					while read line; do
						echo "    $line"
					done < "/proc/asound/card${i}/pcm${j}${t}/sub0/hw_params"
				fi
			done
		done
		echo
	fi
done