Linux script to convert FLAC to MP3

Found this somewhere on the net but have lost the source - apologies if you are the author!

Nice clean script to convert FLAC to MP3. Nice thing is that it leaves it alone if you've already done it... So you can run it again if you've added a few FLACs.  Also, for those albums that I have as MP3 rather than FLAC anyway (e.g. Amazon autorip CDs) the script copies the MP3 across to the copy directory tree, which is just what I want.

Works very nicely on Ubuntu 17.10. Idea is to convert my CD collection (stored as FLAC) into MP3 format for playing in the car on a USB stick.

 build_convert_job.sh 

#!/bin/bash

FLAC_PATH=$1
CONV_PATH=$2

DEBUG=0;

function usage {
  echo "";
  echo "    This script convert all flac files from a folder to mp3 files to a second folder";
  echo "";
  echo "    Usage :";
  echo "        ./conv.sh {Source Folder} {Destination Folder}";
  echo "        note : booth folder must exist before starting this script";
  echo "               files other than flac are copied to the destination folder";
  echo "";
}

if [ ! -d "$2" ]; then
  echo "";
  echo " ERROR : [$2] is not a directory.";
  usage
  exit 1
fi;

if [ ! -d "$2" ]; then
  echo "";
  echo " ERROR : [$2] is not a directory.";
  usage
  exit 1
fi;

COMMANDS="run.sh"
echo "" > run.sh
echo " convert from $FLAC_PATH to $CONV_PATH ";

find "${FLAC_PATH}" -type f |while read myFile; do
  SRC_DIR=${myFile%/*}
  SRC_FILE=${myFile##*/}
  DST_DIR=$CONV_PATH/$SRC_DIR
  mkdir -p "${DST_DIR}"
  # TEST if the file is a flac ....
  metaflac --show-md5sum "${myFile}" 2>/dev/null 1>/dev/null
  if [ $? -eq 0 ]; then
    echo -n "  *** $myFile [FLAC !] : "
    DST_FILE=${myFile%.*}
    OUT_PATH="${DST_DIR}/$( echo $SRC_FILE | sed -e 's/.flac$/.mp3/')"

    if [ $DEBUG == 1 ]; then
      echo "  SRC = $myFile";
      echo "  OUT = $OUT_PATH"
    fi;

    if [ -f "$OUT_PATH" ]; then
      echo "  exist, do nothing !";
    else
      echo "  add to compress list !";
      echo "ffmpeg -y -i \"${myFile}\" -codec:a libmp3lame -q:a 0 -map_metadata 0 -id3v2_version 3 \"${OUT_PATH}\" " >> $COMMANDS
    fi;

  else
     echo -n "  *** $SRC_FILE  [NOT FLAC] : "
     if [ -f "${CONV_PATH}/${myFile}" ]; then
       echo " exist, do nothing !"
     else
       echo "  copy."
       cp "${myFile}" "${CONV_PATH}/${myFile}"
     fi
  fi

done;

echo " And now, CONVERT THE FLAC's!!! "
echo sh run.sh