Q&D flac2mp3 to be used with cron.

ldot-flac2mp3.sh

#!/bin/bash

# Configurables
LOC="${LOC:-$1}"  # You can set LOC via env variable or argument
FLAC_BIN="${FLAC_BIN:-flac}"
METAFLAC_BIN="${METAFLAC_BIN:-metaflac}"
LAME_BIN="${LAME_BIN:-lame}"
ID3_BIN="${ID3_BIN:-id3tag}"
V="${V:-true}" # set to echo to enable debug
W="${W:-true}" # set to echo to enable warnings
# End configurables

if [ -z "$LOC" -o ! -d "$LOC" ]; then
	echo "Invalid LOC" >&2
	exit 1
fi

# Check for utilities
T=0
for BIN in $FLAC_BIN $METAFLAC_BIN $LAME_BIN $ID3_BIN
do
if [ -z "$(which "$BIN")" ]; then
	echo "Missing $BIN" >&2
	T=1
fi
done

if [ $T != 0 ]; then
	exit 1
fi

IFS="
"
for a in $(find "$LOC" -type f -a -iname '*.flac')
do
    OUTF=${a%.$FLAC_BIN}.mp3

	# Convert only if output file doesn't exists or if it's older than flac
	# file
	if [ -e "$OUTF" -a "$OUTF" -nt "$a" ]; then
		$W "Skipping '$a' conversion, output file exists" >&2
		continue
	fi

	# Extract metadata
	ARTIST=`$METAFLAC_BIN "$a" --show-tag=ARTIST | sed s/.*=//g`
	TITLE=`$METAFLAC_BIN "$a" --show-tag=TITLE | sed s/.*=//g`
	ALBUM=`$METAFLAC_BIN "$a" --show-tag=ALBUM | sed s/.*=//g`
	TRACKNUMBER=`$METAFLAC_BIN "$a" --show-tag=TRACKNUMBER | sed s/.*=//g`
	DATE=`$METAFLAC_BIN "$a" --show-tag=DATE | sed s/.*=//g`
	#GENRE=`$METAFLAC_BIN "$a" --show-tag=GENRE | sed s/.*=//g`

	$V -ne "$(basename -- "$a"): "

	# Convert file
	$V -n "converting"
	$FLAC_BIN -s -c -d "$a" | $LAME_BIN --silent -m j -q 0 --vbr-new -V 0 -s 44.1 - "${OUTF}.tmp"
	if [ $? -ne 0 ]; then
		rm -- "${OUTF}.tmp"
		$V -n ": failed"
		continue
	else
		$V -n ": ok"
	fi

	# Sync tags
	$V -n ", tags"
	$ID3_BIN --v2tag --song="$TITLE" --track="${TRACKNUMBER:-0}" --artist="$ARTIST" --album="$ALBUM" --year="$DATE" "${OUTF}.tmp" 1>/dev/null
	if [ $? -ne 0 ]; then
		rm -- "${OUTF}.tmp"
		$V -n ": failed"
		continue
	else
		$V -n ": ok"
	fi

	# Move file to final location
	mv "${OUTF}.tmp" "${OUTF}"
	$V
done