convert wav to mp3 file with ffmep on mac

wav2mp3.sh

#!/usr/bin/env bash
##
##############################################################################
##
##  Script convert wav to mp3 for UN*X
##
##  Dependence:
##      - [ffmpeg](https://ffmpeg.org/)
##
##  Script File:
##      wav2mp3.sh
##
##  Usage:
##      $ uname -v
##      Darwin Kernel Version 14.5.0: Tue Sep  1 21:23:09 PDT 2015; root:xnu-2782.50.1~1/RELEASE_X86_64
##      $ mv ~/download/*.WAV ./
##      $ chmod +x .wav2mp3.sh
##      $ ./wav2mp3.sh
##      $ du -sh *
##      33M  2016-10-14-10-10-05.WAV
##      11M  2016-10-14-10-10-05.mp3
##      4.0K  wav2mp3.sh
##
##############################################################################

for wav in $(find . -name '*.WAV' | sort -r)
do
    mp3=${wav%.*}.mp3

    if [[ -f "${mp3}" ]];
    then
        echo "already converted: ${mp3}"
    else
        echo "converting: ${wav}"
        ffmpeg -i "${wav}" "${mp3}"
    fi
done